150 results on '"D. V. Rose"'
Search Results
2. Impact of power flow on Z-pinch loads
- Author
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K. Tummel, D. R. Welch, D. V. Rose, A. J. Link, and K. R. LeChien
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Condensed Matter Physics - Abstract
Magnetically insulated transmission lines (MITLs) are used to deliver tens of MA to a Z-pinch load. The MITLs suffer current losses due to contaminant plasma located in the anode–cathode gap which is swept toward the load along the power flow. The swept up contaminant plasma can deposit mass and energy onto the load resulting in deformations or the seeding of macroscopic instabilities. This paper discusses 2D fully kinetic simulations of the contaminant plasma evolution which predict the current losses and the flux of mass and energy onto the load. The effects of a dynamic, i.e., imploding, load are shown to increase both the current loss and the mass and energy flux. The MITL used is a conical, radially converging design which is a feature common to MA-scale Z-pinch accelerators.
- Published
- 2022
3. Magnetized particle transport in multi-MA accelerators
- Author
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George Laity, M. E. Cuneo, Nichelle Bennett, D. V. Rose, and Dale Welch
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Physics ,Nuclear and High Energy Physics ,Physics and Astronomy (miscellaneous) ,Diffusion ,QC770-798 ,Surfaces and Interfaces ,Plasma ,Computational physics ,Magnetic field ,Inductance ,Bohm diffusion ,Nuclear and particle physics. Atomic energy. Radioactivity ,Particle ,Ohm ,Joule heating - Abstract
Kinetic simulations of Sandia National Laboratories’ Z machine are conducted to understand particle transport in the highly magnetized environment of a multi-MA accelerator. Joule heating leads to the rapid formation of electrode surface plasmas. These plasmas are implicated in reducing accelerator efficiency by diverting current away from the load [M.R. Gomez et al., Phys. Rev. Accel. Beams 20, 010401 (2017)PRABCJ2469-988810.1103/PhysRevAccelBeams.20.010401, N. Bennett et al., Phys. Rev. Accel. Beams 22, 120401 (2019)PRABCJ2469-988810.1103/PhysRevAccelBeams.22.120401]. The fully-relativistic, electromagnetic simulations presented in this paper show that particles emitted in a space-charge-limited manner, in the absence of plasma, are magnetically insulated. However, in the presence of plasma, particles are transported across the magnetic field in spite of being only weakly collisional. The simulated cross-gap currents are well-approximated by the Hall current in the generalized Ohm’s law. The Hall conductivities are calculated using the simulated particle densities and energies, and the parameters that increase the Hall current are related to transmission line inductance. Analogous to the generalized Ohm’s law, we extend the derivation of the magnetized diffusion coefficients to include the coupling of perpendicular components. These yield a Hall diffusion rate, which is equivalent to the empirical Bohm diffusion.
- Published
- 2021
4. A Primer on Pulsed Power and Linear Transformer Drivers for High Energy Density Physics Applications
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Joshua J. Leckbee, Dale Welch, J. C. Zier, P. C. Campbell, Ryan D. McBride, John Greenly, Aaron Covington, Ronald M. Gilgenbach, B. M. Kovalchuk, Brendan Sporer, J. M. Woolstrum, Akash Shah, Yue Ying Lau, S. M. Miller, S. N. Bland, D. V. Rose, Joseph W. Schumer, Brian Hutsel, Pierre-Alexandre Gourdain, Salvador Portillo, David Yager-Elorriaga, William A. Stygar, A.A. Kim, Bryan V. Oliver, A. M. Steiner, Farhat Beg, Nicholas M. Jordan, Yitzhak Maron, Michael G. Mazarakis, Nicholas Ramey, S. C. Bott-Suzuki, Mark E. Savage, Mark L. Kiefer, Daniel Sinars, George Laity, R. B. Spielman, M. R. Gomez, S. G. Patel, J. D. Douglass, M. E. Cuneo, AWE Plc, Sandia National Laboratories, and U.S Department of Energy
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Nuclear and High Energy Physics ,High energy density physics ,Fluids & Plasmas ,0906 Electrical And Electronic Engineering ,Pulsed power ,Condensed Matter Physics ,01 natural sciences ,010305 fluids & plasmas ,law.invention ,0202 Atomic, Molecular, Nuclear, Particle And Plasma Physics ,law ,0103 physical sciences ,Systems engineering ,010306 general physics ,Transformer - Abstract
The objectives of this tutorial are as follows: 1) to help students and researchers develop a basic understanding of how pulsed-power systems are used to create high-energy-density (HED) matter; 2) to develop a basic understanding of a new, compact, and efficient pulsed-power technology called linear transformer drivers (LTDs); 3) to understand why LTDs are an attractive technology for driving HED physics (HEDP) experiments; 4) to contrast LTDs with the more traditional Marx-generator/pulse-forming-line approach to driving HEDP experiments; and 5) to briefly review the history of LTD technology as well as some of the LTD-driven HEDP research presently underway at universities and research laboratories across the globe. This invited tutorial is part of the Mini-Course on Charged Particle Beams and High-Powered Pulsed Sources, held in conjunction with the 44th International Conference on Plasma Science in May of 2017.
- Published
- 2018
5. Fast hybrid particle-in-cell technique for pulsed-power accelerators
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Dale Welch, C. Thoma, Nichelle Bennett, D. V. Rose, and T. C. Genoni
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Physics ,Nuclear and High Energy Physics ,Physics and Astronomy (miscellaneous) ,Cyclotron ,Surfaces and Interfaces ,Plasma ,Mechanics ,Pulsed power ,Plasma oscillation ,law.invention ,symbols.namesake ,Acceleration ,Physics::Plasma Physics ,law ,symbols ,lcsh:QC770-798 ,Particle ,lcsh:Nuclear and particle physics. Atomic energy. Radioactivity ,Particle-in-cell ,Debye length - Abstract
Hybrid-implicit particle-in-cell (PIC) algorithms permit the simulation of complex problems involving both kinetic and fluid plasma regimes over large spatial and temporal scales. Fluid electrons can be computationally fast where and when fluid assumptions are valid. Additional flexibility is obtained if discrete PIC macroparticles, with velocities advanced by either fluid or kinetic equations, are permitted to dynamically migrate between the two descriptions based on phase space criteria. Ideally, these migrations result in energetic particles treated kinetically and dense thermal plasma particles as a fluid. With an energy-conserving particle advance, resolution of the plasma Debye length is not required for numerical accuracy or stability. For pulsed-power applications, the simulation time step is usually constrained by the electron cyclotron frequency, not the more restrictive plasma frequency. A new implicit technique permits accurate particle orbits even at highly underresolved cyclotron frequencies. Thus, greater temporal and spatial scales can be accurately modeled relative to conventional PIC techniques. In this paper, we describe the hybrid PIC technique and fully electromagnetic, hybrid simulations of plasma evolution and current shunting in an idealized accelerator designed for driving a $Z$-pinch load. The dynamics of electrode heating, electron transport, and surface contaminant evolution are studied in a series of relativistic hybrid-implicit PIC simulations. These dynamics can lead to the shunting of current before reaching the $Z$-pinch load, thus degrading load performance. Examining two previously published power flow problems, we compare results from fully kinetic, multifluid, and hybrid kinetic-fluid simulations and discuss the computational performance of these three options. The key thrust of the work is to identify possible computational acceleration, through hybrid methods, required for accelerator understanding and design.
- Published
- 2020
6. Numerical simulations of enhanced ion current losses in the inner magnetically insulated transmission line of the Z accelerator
- Author
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George Laity, Eduardo Waisman, Dale Welch, Brian Hutsel, D. V. Rose, Nichelle Bennett, M. E. Cuneo, and Michael P. Desjarlais
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Nuclear and High Energy Physics ,Materials science ,Physics and Astronomy (miscellaneous) ,Physics::Plasma Physics ,Transmission line ,lcsh:QC770-798 ,lcsh:Nuclear and particle physics. Atomic energy. Radioactivity ,Ion current ,Surfaces and Interfaces ,Atomic physics - Abstract
Two-dimensional electromagnetic (EM) particle-in-cell (PIC) simulations of a radial magnetically-insulated-transmission-line are presented and compared to the model of E. M. Waisman, M. P. Desjarlais, and M. E. Cuneo [Phys. Rev. Accel. Beams 22, 030402 (2019)PRABCJ2469-988810.1103/PhysRevAccelBeams.22.030402 in the “high-enhancement” (WDC-HE) limit. The simulations use quasi-equilibrium current and voltage values based on the Sandia National Laboratories Z accelerator, with prescribed injection of an electron sheath that gives electron density profiles qualitatively similar to those used in the WDC-HE model. We find that the WDC-HE model accurately predicts the quasiequilibrium ion current losses in the EM PIC simulations for a wide range of current and voltage values. For the case of two ion species where one is magnetically insulated by the ambient magnetic field and the other is not, the charge of the lighter insulated species in the anode-cathode gap can modify the electric field profile, reducing the ion current density enhancement for the heavier ion species. On the other hand, for multiple ion species, when the lighter ions are not magnetically insulated and are a significant fraction of the anode plasma, they dominate the current loss, producing loss currents which are a significant fraction of the lighter ion WDC values. The observation of this effect in the present work is new to the field and may significantly impact the analysis of ion current losses in the Z machine inner MITL and convolute.
- Published
- 2020
7. Electrode contaminant plasma effects in 107 -A Z pinch accelerators
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Dale Welch, D. V. Rose, William A. Stygar, C. Thoma, C. Miller, Nichelle Bennett, and T. C. Genoni
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Physics ,Nuclear and High Energy Physics ,Physics and Astronomy (miscellaneous) ,Electrical resistivity and conductivity ,Z-pinch ,Pinch ,Surfaces and Interfaces ,Plasma ,Radius ,Atomic physics ,Current (fluid) ,Kinetic energy ,Instability - Abstract
The dynamics of electrode heating, sheath flow, and contaminant plasma evolution in Sandia National Laboratories' high-power $Z$ accelerator is studied in a series of 2D relativistic particle-in-cell simulations. These dynamics can lead to the shunting of current before reaching the $Z$ pinch load, thus degrading load performance. Previous work has focused on current diverted in the upstream magnetically insulated transmission lines (MITLs) and post-hole convolute regions of $Z$. In these regions, losses were found to scale strongly with load impedance as well as the system vacuum and were calculated to be as high as 1--2 MA. Downstream from the convolute region in $Z$, current measurement is problematic, leading to a lack of understanding of the loss mechanisms in the small radius ($l3\text{ }\text{ }\mathrm{cm}$) MITL feeding the load. In this paper, we present the first ever 2D fully electromagnetic, fully kinetic simulations of plasma evolution and current shunting in the inner MITL region of $Z$. This region is defined by a radially converging MITL, which is a feature common to MA-scale $Z$ pinch accelerators. The electrodes in this region are rapidly heated via mainly Ohmic or skin depth heating. Plasmas quickly form, and surface contaminants are liberated as the temperatures exceed 700 K. Instabilities lead to a rapid plasma density fill of the inner MITL and subsequent current loss. The instability growth is likely due to the resistivity of the magnetized electrode plasma. The plasma, after exceeding ${10}^{15}\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}3}$ density, leads to an additional 1--2 MA current loss in the inner MITL region.
- Published
- 2019
8. Review of pulsed power-driven high energy density physics research on Z at Sandia
- Author
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Raymond C. Clay, Brian Hutsel, P. W. Lake, Steve MacLaren, J. A. Fisher, Bernardo Farfan, S. Beatty, Ian C. Smith, James E. Bailey, J. S. Custer, R. B. Campbell, Marius Schollmeier, H. T. Barclay, Joshua J. Leckbee, Mark Kimmel, Dale Welch, J. R. Fein, Kelly Hahn, Gordon A. Chandler, Gregory Rochau, William Lewis, Michael A. Mangan, Jens Schwarz, Justin Brown, Kris Beckwith, Dawn G. Flicker, Kumar Raman, Nathan W. Moore, William D. Reinhart, Quinn Looker, Thomas A. Haill, M. J. Speir, Carlos L. Ruiz, J. D. Douglass, M. A. Schaeuble, Seth Root, J. F. Benage, M. Wu, G. Loisel, P. J. Christenson, Jack LeRoy Wise, Maurice Keith Matzen, D. J. Lucero, M. D. Mitchell, Evstati Evstatiev, Michael G. Mazarakis, P. T. Springer, Ella Suzanne Field, E. A. Weinbrecht, Clayton E. Myers, C. Aragon, C. Highstrete, P. A. Jones, C. A. McCoy, Paul Schmit, S. G. Patel, T. Gomez, S. Radovich, William A. Stygar, Ryan D. McBride, M. E. Cuneo, John P. Apruzese, John Giuliani, Timothy D. Pointon, Arati Dasgupta, Eric Harding, N. D. Hamlin, Matthias Geissel, Jonathon Shores, Kyle Robert Cochrane, M. R. Gomez, D. Spencer, John Lee McKenney, C. R. Ball, Mark Herrmann, Thomas James Awe, Patrick Knapp, J. W. Kellogg, Sakun Duwal, Christopher Jennings, A. J. Lopez, Marcus D. Knudson, R. J. Kamm, J. Ward Thornhill, Patrick K. Rambo, G. R. McKee, Christine Anne Coverdale, E.M. Campbell, Timothy McGuire Flanagan, P. Kalita, Michael P. Desjarlais, M. H. Hess, P. Gard, Kevin Baker, J.-P. Davis, Roger Alan Vesey, Tommy Ao, Thomas R. Mattsson, G. A. Shipley, A. Kreft, Raymond W. Lemke, G. S. Dunham, David Yager-Elorriaga, Matthew Martin, G. Natoni, R. J. Leeper, Brian Stoltzfus, D. J. Ampleford, Aaron Edens, C. Tyler, P. E. Wakeland, Taisuke Nagayama, Drew Johnson, E. B. Christner, Rudolph J. Magyar, G. T. Leifeste, Timothy J. Webb, D. Sandoval, D. V. Rose, M. C. Jones, D. Headley, Andrew Baczewski, Derek C. Lamppa, Sean Simpson, Adam B Sefkow, Kevin N. Austin, B. A. Branch, P. E. Specht, Kyle Peterson, Daniel Sinars, George Laity, M. D. Christison, Harry McLean, A. M. Steiner, M. D. Furnish, S. A. Lewis, A. J. Harvey-Thompson, Benjamin R. Galloway, Edmund Yu, W. L. Langston, K. Chandler, D. G. Chacon, A. R. Miles, C. S. Alexander, M. J. Edwards, A. Yu, Christopher Jay Bourdon, M. R. Weis, J. H. Hammer, Brent Manley Jones, B. M. Cook, Luke Shulenburger, J. A. Mills, S. A. Slutz, Anthony P. Colombo, A. J. Maurer, Karen Blaha, Gary Grim, Kate Bell, C. S. Speas, Christopher T Seagle, Nichelle Bennett, John L. Porter, Daniel H. Dolan, H. L. Hanshaw, M. A. Sweeney, T. A. Gardiner, J. J. Boerner, David B. Seidel, M. E. Sceiford, Jose A. Torres, Stephanie Hansen, Mark E. Savage, Daniel Ruiz, Andrew Porwitzky, D. J. Armstrong, O. Johns, A. C. Owen, Mark D. Johnston, Omar Hurricane, J. S. Lash, K. R. LeChien, David E. Bliss, Michael E. Glinsky, Joshua P. Townsend, Dean C. Rovang, G. K. Robertson, and Mark L. Kiefer
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Physics ,Nuclear engineering ,Electric potential energy ,Plasma ,Pulsed power ,Radiation ,Condensed Matter Physics ,01 natural sciences ,010305 fluids & plasmas ,law.invention ,Capacitor ,law ,0103 physical sciences ,Current (fluid) ,010306 general physics ,Inertial confinement fusion ,Energy (signal processing) - Abstract
Pulsed power accelerators compress electrical energy in space and time to provide versatile experimental platforms for high energy density and inertial confinement fusion science. The 80-TW “Z” pulsed power facility at Sandia National Laboratories is the largest pulsed power device in the world today. Z discharges up to 22 MJ of energy stored in its capacitor banks into a current pulse that rises in 100 ns and peaks at a current as high as 30 MA in low-inductance cylindrical targets. Considerable progress has been made over the past 15 years in the use of pulsed power as a precision scientific tool. This paper reviews developments at Sandia in inertial confinement fusion, dynamic materials science, x-ray radiation science, and pulsed power engineering, with an emphasis on progress since a previous review of research on Z in Physics of Plasmas in 2005.
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- 2020
9. Conceptual design of a 960-TW accelerator powered by impedance-matched Marx generators
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C. Verdon, D. Muron, J. K. Moore, Joshua J. Leckbee, Brian Hutsel, M. R. Gomez, Mark Herrmann, Dale Welch, M. Wisher, O. Johns, E. W. Breden, G. W. Greiser, Daniel Sinars, George Laity, M. H. Hess, R. F. Schneider, J. Calhoun, P. A. Jones, J. B. Ennis, K.K. Matzen, K. Austin, Ronald M. Gilgenbach, Pierre Gourdain, M. E. Sceiford, C. B. Mostrom, M. C. Jones, R. B. Spielman, R. A. Cooper, Roger Alan Vesey, T. D. Mulville, J. Edwards, J. Hammer, K. LeChien, Christopher Jennings, D. Pilkington, Ryan D. McBride, B. Stoltzfus, Mark E. Savage, Gregory Rochau, F. R. Gruner, D. J. Lucero, D. V. Rose, R. McKee, Derek C. Lamppa, William A. Stygar, D. O. Jobe, M. E. Cuneo, G. Brent, R. E. Clark, Kyle Peterson, James E. Bailey, Kumar Raman, Brent Manley Jones, S. A. Slutz, Eduardo Waisman, K. Keilholtz, E. A. Weinbrecht, Michael G. Mazarakis, S. A. Lewis, Matthew Martin, Paul Schmit, Thomas James Awe, M. Campbell, Patrick Knapp, and John L. Porter
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Physics ,Thermonuclear fusion ,010308 nuclear & particles physics ,business.industry ,Electrical engineering ,01 natural sciences ,010305 fluids & plasmas ,law.invention ,Inductance ,Capacitor ,Electric power transmission ,Stack (abstract data type) ,Conceptual design ,law ,0103 physical sciences ,Electric power ,business ,Electrical impedance - Abstract
We have developed a conceptual design of a next-generation pulsed-power accelerator that is optimized for advanced high-energy-density-physics experiments. The prime power source of the machine consists of 210 impedance-matched Marx generators (IMGs). Each IMG drives a 150-ns-long coaxial-transmission-line impedance transformer. The coaxial lines provide a minimum of 300 ns of transit-time isolation between each pair of IMGs. The lines in turn drive six radial-transmission-line impedance transformers, which transport the power generated by the IMGs to a six-level vacuum-insulator stack. The stack is connected to six conical outer magnetically insulated vacuum transmission lines (MITLs); these are joined in parallel at a 12-cm radius by a triple-post-hole vacuum convolute. The convolute sums the electrical currents at the outputs of the six outer MITLs, and delivers the combined current to a single short inner MITL. The inner MITL transmits the combined current to the accelerator's physics load. Since the accelerator would be the largest and most-powerful pulsed-power machine developed to date, we refer to it as Jupiter. The conceptual design of Jupiter is 72 m in diameter, stores 140 MJ of electrical energy, and generates 960 TW of peak electrical power at the output of the IMG system. The design delivers 2700 TW, 67 MA, and 9.2 MJ in a 110-ns pulse to a 0D magnetized-liner inertial-fusion (MagLIF) target. The principal goal of the design is to achieve high-yield thermonuclear fusion; i.e., a fusion yield that exceeds the energy initially stored by the accelerator's capacitors.
- Published
- 2017
10. Theory and Circuit Model for Lossy Coaxial Transmission Line
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Richard E. Clark, Dale Welch, T. C. Genoni, C. Anderson, J. Gansz-Torres, and D. V. Rose
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Physics ,Acoustics ,Lossy compression ,Coaxial transmission line - Published
- 2017
11. Experimental study of current loss and plasma formation in the Z machine post-hole convolute
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Eduardo Waisman, Yitzhak Maron, Ryan D. McBride, M. E. Cuneo, Ronald M. Gilgenbach, Christopher Jennings, M. R. Gomez, Brian Hutsel, D. V. Rose, and William A. Stygar
- Subjects
Nuclear and High Energy Physics ,Materials science ,Physics and Astronomy (miscellaneous) ,Plasma formation ,010308 nuclear & particles physics ,Surfaces and Interfaces ,Plasma ,Pulsed power ,01 natural sciences ,010305 fluids & plasmas ,Physics::Plasma Physics ,Physics::Space Physics ,0103 physical sciences ,lcsh:QC770-798 ,lcsh:Nuclear and particle physics. Atomic energy. Radioactivity ,Current (fluid) ,Atomic physics ,Plasma density - Abstract
The Z pulsed-power generator at Sandia National Laboratories drives high energy density physics experiments with load currents of up to 26 MA. Z utilizes a double post-hole convolute to combine the current from four parallel magnetically insulated transmission lines into a single transmission line just upstream of the load. Current loss is observed in most experiments and is traditionally attributed to inefficient convolute performance. The apparent loss current varies substantially for z-pinch loads with different inductance histories; however, a similar convolute impedance history is observed for all load types. This paper details direct spectroscopic measurements of plasma density, temperature, and apparent and actual plasma closure velocities within the convolute. Spectral measurements indicate a correlation between impedance collapse and plasma formation in the convolute. Absorption features in the spectra show the convolute plasma consists primarily of hydrogen, which likely forms from desorbed electrode contaminant species such as H_{2}O, H_{2}, and hydrocarbons. Plasma densities increase from 1×10^{16} cm^{−3} (level of detectability) just before peak current to over 1×10^{17} cm^{−3} at stagnation (tens of ns later). The density seems to be highest near the cathode surface, with an apparent cathode to anode plasma velocity in the range of 35–50 cm/μs. Similar plasma conditions and convolute impedance histories are observed in experiments with high and low losses, suggesting that losses are driven largely by load dynamics, which determine the voltage on the convolute.
- Published
- 2017
12. Benchmarking Astrophysical Jet Simulations
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J. H. Beall, D. V. Rose, M. T. Wolff, and K. Lind
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Nuclear physics ,Physics ,Astrophysical jet ,Benchmarking - Published
- 2016
13. Transition from Beam-Target to Thermonuclear Fusion in High-Current DeuteriumZ-Pinch Simulations
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Anthony Link, Dustin Offermann, D. V. Rose, Carsten Thoma, C. B. Mostrom, Andrea Schmidt, Dale Welch, and R. E. Clark
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Physics ,Thermonuclear fusion ,Lawson criterion ,General Physics and Astronomy ,Plasma ,01 natural sciences ,Instability ,010305 fluids & plasmas ,Nuclear physics ,Electric field ,Z-pinch ,0103 physical sciences ,Pinch ,010306 general physics ,Scaling - Abstract
Fusion yields from dense, $Z$-pinch plasmas are known to scale with the drive current, which is favorable for many potential applications. Decades of experimental studies, however, show an unexplained drop in yield for currents above a few mega-ampere (MA). In this work, simulations of DD $Z$-Pinch plasmas have been performed in 1D and 2D for a constant pinch time and initial radius using the code Lsp, and observations of a shift in scaling are presented. The results show that yields below 3 MA are enhanced relative to pure thermonuclear scaling by beamlike particles accelerated in the Rayleigh-Taylor induced electric fields, while yields above 3 MA are reduced because of energy lost by the instability and the inability of the beamlike ions to enter the pinch region.
- Published
- 2016
14. Simulations of Dynamic Laser/Plasma X-Ray Production
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R. B. Campbell, Dale Welch, C. L. Miller, Dawn G. Flicker, Bryan V. Oliver, D. V. Rose, and Timothy J. Webb
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Physics ,Nuclear and High Energy Physics ,business.industry ,Bremsstrahlung ,Plasma ,Radiation ,Condensed Matter Physics ,Laser ,Fluence ,Pulse (physics) ,law.invention ,Optics ,law ,Relativistic electron beam ,Atomic physics ,business ,Beam (structure) - Abstract
Intense laser beams focused onto thin high-atomic-number targets can generate short intense bursts of MeV X-rays from a small area of the target. Such systems are being developed as short-pulse point-projection X-ray sources for imaging high-density objects. Here, large-scale (400-million macroparticles and 15-million grid cells) 3-D particle-in-cell simulations are described that model the dynamic interaction between the laser beam, a blowoff plasma layer, and the solid-density target. The simulations self-consistently treat the nonlinear interaction between the incident laser pulse and the blowoff plasma layer where a relativistic electron beam is generated. This beam propagates into the solid-density high-atomic-number target where MeV bremsstrahlung is generated. The model tracks the generation, propagation, and self-absorption of radiation in the blowoff plasma, target, and beyond. Radiation production (fluence and energy spectrum) is characterized in the simulations as a function transverse target size, laser-injection angle, and laser energy. The simulated X-ray fluence for the case of a 45 °-angle-of-incidence 100-J 0.5-ps laser pulse with a 6- μm FWHM focus produces a peak dose in excess of 0.2 rad from a 10-μm-thick square gold target, consistent with experimental measurements.
- Published
- 2012
15. STUDIES OF BREAKDOWN IN A PRESSURIZED RF CAVITY
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M. Kuchnir, D. Newsham, Milorad Popovic, M. BastaniNejad, Dale Welch, A.A. Elmustafa, Carsten Thoma, P. Hanlet, M. Alsharo'a, Alfred Moretti, D. V. Rose, Daniel M. Kaplan, Rolland Johnson, Charles M. Ankenbrandt, and Katsuya Yonehara
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Physics ,Nuclear and High Energy Physics ,Hydrogen ,Surface gradient ,chemistry.chemical_element ,Astronomy and Astrophysics ,Electron ,Tungsten ,Atomic and Molecular Physics, and Optics ,law.invention ,chemistry ,law ,Electrode ,Work function ,Atomic physics ,Beryllium ,Scanning tunneling microscope - Abstract
Microscopic images of the surfaces of metallic electrodes used in high-pressure gas-filled 805 MHz RF cavity experiments1 have been used to investigate the mechanism of RF breakdown.2 The images show evidence for melting and boiling in small regions of ~10 micron diameter on tungsten, molybdenum, and beryllium electrode surfaces. In these experiments, the dense hydrogen gas in the cavity prevents electrons or ions from being accelerated to high enough energy to participate in the breakdown process so that the only important variables are the fields and the metallic surfaces. The distributions of breakdown remnants on the electrode surfaces are compared to the maximum surface gradient E predicted by an ANSYS model of the cavity. The local surface density of spark remnants, proportional to the probability of breakdown, shows a strong exponential dependence on the maximum gradient, which is reminiscent of Fowler-Nordheim behavior of electron emission from a cold cathode. New simulation results have shown good agreement with the breakdown behavior of the hydrogen gas in the Paschen region and have suggested improved behavior with the addition of trace dopants such as SF 6.3 Present efforts are to extend the computer model to include electrode breakdown phenomena and to use scanning tunneling microscopy to search for work function differences between the conditioned and unconditioned parts of the electrodes.
- Published
- 2011
16. Excitation of electromagnetic whistler waves due to a parametric interaction between magnetosonic and lower oblique resonance modes in a cold, magnetized plasma
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D. V. Rose, James Caplinger, V. I. Sotnikov, and Daniel Main
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Physics ,010504 meteorology & atmospheric sciences ,Whistler ,Loop antenna ,Resonance ,Condensed Matter Physics ,Lower hybrid oscillation ,01 natural sciences ,010305 fluids & plasmas ,Computational physics ,Physics::Space Physics ,0103 physical sciences ,Extremely low frequency ,Very low frequency ,Antenna (radio) ,Magnetic dipole ,Computer Science::Information Theory ,0105 earth and related environmental sciences - Abstract
We have studied the parametric interaction between a fast magnetosonic (FM) mode and a lower oblique resonance (LOR) mode in a cold, magnetized plasma using a kinetic, three dimensional Particle-in-Cell simulation code called the Large Scale Plasma. The FM mode is excited with a loop antenna driven at a frequency below the lower hybrid frequency (ωLH), while the LOR is excited at a frequency above ωLH. For historical purposes explained in the Introduction, we call the antennas which drive the FM mode and LOR mode Extremely Low Frequency (ELF) and Very Low Frequency (VLF) antennas, respectively. The antennas are modeled as magnetic dipoles (ρant = 0) and are assigned a time varying current density within a finite sized current loop. The VLF and ELF antennas are driven at 10 A and 3 A, respectively. The parametric interaction is excited with a combined ELF/VLF antenna (which we call a parametric antenna) and includes both antennas driven simultaneously in the same simulation domain. We show that the parametric antenna non-linearly excites electromagnetic (EM) whistler waves to a greater extent than the VLF antenna alone. We also show that the parametric excitation of EM whistler waves leads to greater emitted EM power (measured in Watts) compared with a VLF antenna alone.We have studied the parametric interaction between a fast magnetosonic (FM) mode and a lower oblique resonance (LOR) mode in a cold, magnetized plasma using a kinetic, three dimensional Particle-in-Cell simulation code called the Large Scale Plasma. The FM mode is excited with a loop antenna driven at a frequency below the lower hybrid frequency (ωLH), while the LOR is excited at a frequency above ωLH. For historical purposes explained in the Introduction, we call the antennas which drive the FM mode and LOR mode Extremely Low Frequency (ELF) and Very Low Frequency (VLF) antennas, respectively. The antennas are modeled as magnetic dipoles (ρant = 0) and are assigned a time varying current density within a finite sized current loop. The VLF and ELF antennas are driven at 10 A and 3 A, respectively. The parametric interaction is excited with a combined ELF/VLF antenna (which we call a parametric antenna) and includes both antennas driven simultaneously in the same simulation domain. We show that the paramet...
- Published
- 2018
17. The Science and Technologies for Fusion Energy With Lasers and Direct-Drive Targets
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Nasr M. Ghoniem, A. Bozek, S. Zenobia, Jaafar A. El-Awady, J.L. Weaver, Matthew F. Wolford, S.M. Gidcumb, Nicole Petta, Craig L. Olson, Dennis L. Sadowski, Timothy J. Renk, John J. Karnes, Kathleen I. Schaffers, J. Caird, D. Weidenheimer, James K. Hoffer, T. Bernat, J. Hund, Lane Carlson, H. Sanders, K. Schoonover, G. Sviatoslavsky, J.E. Streit, A.R. Raffray, A.E. Robson, D Harding, Maximilian B. Gorensek, Farrokh Najmabadi, Diana Grace Schroen, D. V. Rose, James Blanchard, Robert Lehmberg, Gerald L. Kulcinski, L.J. Perkins, C. Ebbers, Drew Geller, K.-J. Boehm, G. Romanoski, J F Latkowski, T Lehecka, D Forsythe, S C. Glidden, John Giuliani, D.T. Goodin, D. Morton, Frank Hegeler, Keith J. Leonard, Shahram Sharafat, W. Parsells, M. W. McGeoch, Q. Hu, Wayne R. Meier, S B Gilliam, Neil Alexander, Mark S. Tillack, G.W. Flint, I. D. Smith, Gregory A. Moses, John D. Sheliak, Andrew J. Schmitt, C Prinksi, S O'Dell, S. P. Obenschain, E. Marriott, M Bobecia, C. Gentile, John D. Sethian, Chad E. Duty, T. Kozub, Lance Lewis Snead, R.W. Petzoldt, Ahmad M. Ibrahim, M.C. Myers, John F. Santarius, Steven J. Zinkle, Moshe Friedman, D. Bittner, Denis Colombant, R. Radell, R. Paguio, Thad Heltemes, Andy J. Bayramian, T. Dodson, W.J. Hogan, J. Pulsifer, N R Parikh, S. Abdel Kahlik, and Mohamed E. Sawan
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Nuclear and High Energy Physics ,Thermonuclear fusion ,Gas laser ,Power station ,business.industry ,Computer science ,Fusion power ,Condensed Matter Physics ,Laser ,law.invention ,Electricity generation ,Optics ,law ,Diode-pumped solid-state laser ,Aerospace engineering ,business ,Inertial confinement fusion - Abstract
We are carrying out a multidisciplinary multi-institutional program to develop the scientific and technical basis for inertial fusion energy (IFE) based on laser drivers and direct-drive targets. The key components are developed as an integrated system, linking the science, technology, and final application of a 1000-MWe pure-fusion power plant. The science and technologies developed here are flexible enough to be applied to other size systems. The scientific justification for this work is a family of target designs (simulations) that show that direct drive has the potential to provide the high gains needed for a pure-fusion power plant. Two competing lasers are under development: the diode-pumped solid-state laser (DPPSL) and the electron-beam-pumped krypton fluoride (KrF) gas laser. This paper will present the current state of the art in the target designs and lasers, as well as the other IFE technologies required for energy, including final optics (grazing incidence and dielectrics), chambers, and target fabrication, injection, and tracking technologies. All of these are applicable to both laser systems and to other laser IFE-based concepts. However, in some of the higher performance target designs, the DPPSL will require more energy to reach the same yield as with the KrF laser.
- Published
- 2010
18. Laser IFE Direct Drive Chamber Concepts with Magnetic Intervention
- Author
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C.A. Gentile, Mohamed E. Sawan, A.E. Robson, John D. Sethian, A.R. Raffray, D. V. Rose, and E. Marriott
- Subjects
Nuclear and High Energy Physics ,Materials science ,020209 energy ,Mechanical Engineering ,Nuclear engineering ,02 engineering and technology ,Laser ,01 natural sciences ,010305 fluids & plasmas ,law.invention ,Nuclear magnetic resonance ,Nuclear Energy and Engineering ,law ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,General Materials Science ,Civil and Structural Engineering - Abstract
The High Average Power Laser (HAPL) program is focusing on the development of laser IFE power plants based on lasers, direct-drive targets and dry wall chambers. One key issue is the survival of the chamber wall under the ion threat spectra (representing ~25% of the yield energy). The possibility of steering the ions away from the chamber to specially-designed dump chambers using magnetic intervention is being investigated. This brings up the intriguing possibility of utilizing a liquid wall to accommodate the ion fluxes in the dump chamber provided the right measures are taken to prevent the liquid from contaminating the main chamber. This paper covers the initial assessment of different magnetic configurations for a laser IFE chamber. Their key characteristics are described results of the supporting design analyses are summarized and the major findings and issues are highlighted.
- Published
- 2009
19. Plans for longitudinal and transverse neutralized beam compression experiments, and initial results from solenoid transport experiments
- Author
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Dale Welch, D. Baca, David P. Grote, Joshua Coleman, Enrique Henestroza, J.-L. Vay, F.M. Bieniosek, Peter A. Seidl, A.W. Molvik, Prabir K. Roy, Ronald C. Davidson, Adam B Sefkow, B.G. Logan, W.L. Waldron, Aharon Friedman, D. V. Rose, W.M. Sharp, Matthaeus Leitner, Simon S. Yu, Igor Kaganovich, Erik P. Gilson, Irving Haber, Julien Armijo, and P. C. Efthimion
- Subjects
Physics ,Nuclear and High Energy Physics ,Ion beam ,business.industry ,Cyclotron ,Solenoid ,Warm dense matter ,Ion ,law.invention ,Transverse plane ,Optics ,law ,Physics::Accelerator Physics ,Laser beam quality ,Atomic physics ,business ,Instrumentation ,Beam (structure) - Abstract
This paper presents plans for neutralized drift compression experiments, precursors to future target heating experiments. The target-physics objective is to study warm dense matter (WDM) using short-duration (∼1 ns) ion beams that enter the targets at energies just above that at which dE/dx is maximal. High intensity on target is to be achieved by a combination of longitudinal compression and transverse focusing. This work will build upon recent success in longitudinal compression, where the ion beam was compressed lengthwise by a factor of more than 50 by first applying a linear head-to-tail velocity tilt to the beam, and then allowing the beam to drift through a dense, neutralizing background plasma. Studies on a novel pulse line ion accelerator were also carried out. It is planned to demonstrate simultaneous transverse focusing and longitudinal compression in a series of future experiments, thereby achieving conditions suitable for future WDM target experiments. Future experiments may use solenoids for transverse focusing of un-neutralized ion beams during acceleration. Recent results are reported in the transport of a high-perveance heavy ion beam in a solenoid transport channel. The principal objectives of this solenoid transport experiment are to match and transport a space-charge-dominated ion beam, and to study associated electron-cloud and gas effects that may limit the beam quality in a solenoid transport system. Ideally, the beam will establish a Brillouin-flow condition (rotation at one-half the cyclotron frequency). Other mechanisms that potentially degrade beam quality are being studied, such as focusing-field aberrations, beam halo, and separation of lattice focusing elements.
- Published
- 2007
20. Computational analysis of current-loss mechanisms in a post-hole convolute driven by magnetically insulated transmission lines
- Author
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William A. Stygar, D. V. Rose, M. E. Cuneo, C. B. Mostrom, E. A. Madrid, D.R. Welch, and R. E. Clark
- Subjects
Physics ,Nuclear and High Energy Physics ,Electric power transmission ,Physics and Astronomy (miscellaneous) ,Physics::Plasma Physics ,Transmission line ,lcsh:QC770-798 ,lcsh:Nuclear and particle physics. Atomic energy. Radioactivity ,Nanotechnology ,Surfaces and Interfaces ,Computational analysis ,Current (fluid) ,Engineering physics - Abstract
Numerical simulations of a vacuum post-hole convolute driven by magnetically insulated vacuum transmission lines (MITLs) are used to study current losses due to charged particle emission from the MITL-convolute-system electrodes. This work builds on the results of a previous study [E. A. Madrid et al. Phys. Rev. ST Accel. Beams 16, 120401 (2013)PRABFM1098-440210.1103/PhysRevSTAB.16.120401] and adds realistic power pulses, Ohmic heating of anode surfaces, and a model for the formation and evolution of cathode plasmas. The simulations suggest that modestly larger anode-cathode gaps in the MITLs upstream of the convolute result in significantly less current loss. In addition, longer pulse durations lead to somewhat greater current loss due to cathode-plasma expansion. These results can be applied to the design of future MITL-convolute systems for high-current pulsed-power systems.
- Published
- 2015
21. Energetics of Jet Interactions with the Intracluster Medium
- Author
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J. H. Beall, J. Guillory, Sabine Schindler, Sergio Colafrancesco, and D. V. Rose
- Subjects
Physics ,Radio galaxy ,Astrophysics::High Energy Astrophysical Phenomena ,Astronomy ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Galaxy merger ,Galaxy groups and clusters ,Space and Planetary Science ,Galaxy group ,Intracluster medium ,Elliptical galaxy ,Lenticular galaxy ,Astrophysics::Galaxy Astrophysics ,Galaxy cluster - Abstract
An interpretation of X-ray observations of the (intracluster) gas in galaxy clusters, when combined with significant numerical work in simulating cluster formation, suggests that an additional heating mechanism is required to explain the dynamics and temperature profile in the intracluster medium (ICM). In addition to shock heating, star formation, and supernovae, a likely candidate for a heating mechanism for the ICM comes from the jets of material originating in the cores of active radio galaxies, themselves located in the cores of clusters. These large-scale jets propagate outward from the core of the galaxy into the intracluster medium. In this paper, we discuss the origin and energetics of these jets, the mechanisms of their propagation and energy loss, their constitution, and the likely consequences of their interactions with the intracluster medium in clusters of galaxies.
- Published
- 2006
22. Impact of magnetic diversion on laser IFE reactor design and performance
- Author
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A. R. Raffray, J. Blanchard, A. E. Robson, D. V. Rose, M. Sawan, J. Sethian, L. Snead, I. Sviatoslavsky, and the HAPL Team the HAPL Team
- Subjects
Engineering ,ComputingMethodologies_SIMULATIONANDMODELING ,business.industry ,Nuclear engineering ,General Physics and Astronomy ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,Scoping study ,Key issues ,Reactor design ,Laser ,law.invention ,law ,business ,Engineering design process - Abstract
This paper covers the results of a scoping study to assess the possible application of magnetic diversion to a laser IFE reactor. Its impact on the engineering design and performance of the reactor is discussed, key issues are identified, and the findings from this assessment are summarized.
- Published
- 2006
23. US heavy ion beam research for high energy density physics applications and fusion
- Author
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R.J. Briggs, Debra Callahan, W.L. Waldron, Max Tabak, Enrique Henestroza, David P. Grote, Christine M. Celata, Edward A. Startsev, Erik P. Gilson, J.-L. Vay, G.A. Westenskow, W.W. Lee, Simon S. Yu, M. Kireeff Covo, Prabir K. Roy, Larry R. Grisham, S.M. Lund, Dale Welch, Hong Qin, Craig L. Olson, J.W. Kwan, F.M. Bieniosek, Carsten Thoma, Wayne R. Meier, Ronald C. Davidson, Jonathan Wurtele, B.G. Logan, Peter A. Seidl, Ronald H. Cohen, W.M. Sharp, Matthaeus Leitner, P. C. Efthimion, A.W. Molvik, Edward P. Lee, Igor Kaganovich, J.J. Barnard, D. V. Rose, Shmuel Eylon, Aharon Friedman, Joshua Coleman, C.S. Debonnel, Adam B Sefkow, and Gregory Penn
- Subjects
High Energy Density Matter ,Ion beam ,Chemistry ,Nuclear engineering ,General Physics and Astronomy ,Particle accelerator ,Warm dense matter ,Fusion power ,Linear particle accelerator ,Ion ,law.invention ,Nuclear physics ,Physics::Plasma Physics ,law ,Inertial confinement fusion - Abstract
Key scientific results from recent experiments, modeling tools, and heavy ion accelerator research are summarized that explore ways to investigate the properties of high energy density matter in heavy-ion-driven targets, in particular, strongly-coupled plasmas at 0.01 to 0.1 times solid density for studies of warm dense matter, which is a frontier area in high energy density physics. Pursuit of these near-term objectives has resulted in many innovations that will ultimately benefit heavy ion inertial fusion energy. These include: neutralized ion beam compression and focusing, which hold the promise of greatly improving the stage between the accelerator and the target chamber in a fusion power plant; and the Pulse Line Ion Accelerator (PLIA), which may lead to compact, low-cost modular linac drivers.
- Published
- 2006
24. Two-stream stability assessment of intense heavy ion beams propagating in a plasma immersed in an axial magnetic field
- Author
-
Dale Welch, Edward P. Lee, D. V. Rose, and T.C. Genoni
- Subjects
Physics ,Nuclear and High Energy Physics ,Two-stream instability ,Ion beam ,Physics::Plasma Physics ,Plasma ,Electron ,Atomic physics ,Fusion power ,Ion gun ,Instrumentation ,Saturation (magnetic) ,Magnetic field - Abstract
The stability of intense heavy ion beams propagating in preformed plasmas is being assessed for heavy-ion fusion reactor chamber parameters. A dispersion analysis is used to determine unstable two-stream modes for charge- and current-neutralized heavy ion beams propagating in a cold background plasma. Growth rates are compared directly with 2D particle-in-cell simulations. These simulations are also examined to determine saturation amplitudes of the electron thermal energy as well as any deleterious effects on the ion beam.
- Published
- 2005
25. A final focus model for heavy-ion fusion driver system codes
- Author
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Enrique Henestroza, Simon S. Yu, Wayne R. Meier, D. V. Rose, Igor Kaganovich, Dale Welch, B.G. Logan, Parthiban Santhanam, Roger O. Bangerter, W.M. Sharp, and J.J. Barnard
- Subjects
Physics ,Nuclear and High Energy Physics ,business.industry ,Particle accelerator ,Radius ,Fusion power ,Space charge ,law.invention ,Optics ,law ,Magnet ,Chromatic aberration ,Thermal emittance ,business ,Instrumentation ,Beam (structure) - Abstract
The need to reach high temperatures in an inertial fusion energy (IFE) target (or a target for the study of High Energy Density Physics, HEDP) requires the ability to focus ion beams down to a small spot. System models indicate that within the accelerator, the beam radius will be of the order of centimeters, whereas at the final focal spot on the target, a beam radius of the order of millimeters is required, so radial compression factors of order ten are required. The IFE target gain (and hence the overall cost of electricity) and the HEDP target temperature are sensitive functions of the final spot radius on target. Because of this sensitivity, careful attention needs to be paid to the spot radius calculation. We review our current understanding of the elements that enter into a systems model (such as emittance growth from chromatic, geometric, and non-linear space charge forces) for the final focus based on a quadrupolar magnet system.
- Published
- 2005
26. Neutralized transport experiment
- Author
-
Enrique Henestroza, Ronald C. Davidson, W.L. Waldron, André Anders, Simon S. Yu, W.M. Sharp, Dale Welch, B.G. Logan, F.M. Bieniosek, P. C. Efthimion, D. Shuman, Prabir K. Roy, Erik P. Gilson, Wayne G. Greenway, D.L. Vanecek, Carsten Thoma, Adam B Sefkow, Igor Kaganovich, D. V. Rose, and Shmuel Eylon
- Subjects
Physics ,Nuclear and High Energy Physics ,Ion beam deposition ,Ion beam ,Quadrupole ,Thermal emittance ,Plasma ,Beam emittance ,Atomic physics ,Instrumentation ,Beam (structure) ,Perveance - Abstract
Experimental details on providing active neutralization of high brightness ion beam have been demonstrated for Heavy Ion Fusion program. A K + beam was extracted from a variable–perveance injector and transported through 2.4 m long quadrupole lattice for final focusing. Neutralization was provided by a localized cathode arc plasma plug and a RF volume plasma system. Effects of beam perveance, emittance, convergence focusing angle, and axial focusing position on neutralization have been investigated. Good agreement has been observed with theory and experiment throughout the study. r 2005 Elsevier B.V. All rights reserved. PACS: 52.59.Bi,Fn; 29.27.� a; 52.40.Mj; 41.75.Fr,Ht; 29.27.� a
- Published
- 2005
27. Overview of US heavy-ion fusion progress and plans
- Author
-
Christine M. Celata, Ronald C. Davidson, Simon C. M. Yu, Igor Kaganovich, Edward A. Startsev, P. C. Efthimion, A.W. Molvik, Ronald H. Cohen, M. Kireeff Covo, Edward P. Lee, L. Prost, J.J. Barnard, Patrick G. O'Shea, Irving Haber, Matthaeus Leitner, Dale Welch, Aharon Friedman, R. A. Kishek, Debra Callahan, W.L. Waldron, Larry R. Grisham, F.M. Bieniosek, Enrique Henestroza, Prabir K. Roy, Hong Qin, Grant Logan, David P. Grote, Craig L. Olson, Peter A. Seidl, Erik P. Gilson, Wayne R. Meier, Shmuel Eylon, J.-L. Vay, D. V. Rose, S.M. Lund, and J.W. Kwan
- Subjects
Physics ,Nuclear and High Energy Physics ,Particle accelerator ,Plasma ,Fusion power ,Linear particle accelerator ,law.invention ,Nuclear physics ,law ,Quadrupole ,Physics::Accelerator Physics ,Thermal emittance ,Beam emittance ,Instrumentation ,Beam (structure) - Abstract
Significant experimental and theoretical progress has been made in the US heavy-ion fusion program on high-current sources, injectors, transport, final focusing, chambers and targets for high-energy density physics (HEDP) and inertial fusion energy (IFE) driven by induction linac accelerators. One focus of present research is the beam physics associated with quadrupole focusing of intense, space–charge dominated heavy-ion beams, including gas and electron cloud effects at high currents, and the study of long-distance-propagation effects such as emittance growth due to field errors in scaled experiments. A second area of emphasis in present research is the introduction of background plasma to neutralize the space charge of intense heavy-ion beams and assist in focusing the beams to a small spot size. In the near future, research will continue in the above areas, and a new area of emphasis will be to explore the physics of neutralized beam compression and focusing to high intensities required to heat targets to high-energy density conditions as well as for inertial fusion energy.
- Published
- 2005
28. Heavy ion fusion (HIF) driver point designs
- Author
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Peter A. Seidl, C.S. Debonnel, A. Faltens, J.W. Kwan, Ronald C. Davidson, Edward P. Lee, R.J. Briggs, B.G. Logan, Enrique Henestroza, J.J. Barnard, Debra Callahan, G.L. Sabbi, David P. Grote, J F Latkowski, Per F. Peterson, Simon S. Yu, Shmuel Eylon, W.M. Sharp, Prabir K. Roy, P. Heitzenroeder, D. V. Rose, Igor Kaganovich, Dale Welch, Roger O. Bangerter, Ryan P. Abbott, Aharon Friedman, and Christine M. Celata
- Subjects
Nuclear physics ,Physics ,Nuclear and High Energy Physics ,Design studies ,Fusion ,business.industry ,Design study ,Heavy ion ,Point (geometry) ,Control engineering ,Modular design ,business ,Instrumentation - Abstract
In this paper we report on two Heavy Ion Fusion (HIF) driver point design studies. The Robust Point Design (RPD) was completed over a year ago, and the Modular Point Design (MPD) is still in progress. The goal of any point design study is to construct a detailed design that is self-consistent and integrated from injector to target. This has been the primary theme of both studies.
- Published
- 2005
29. Development Path for Z-Pinch IFE
- Author
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Roger Alan Vesey, Riccardo Bonazza, Pattrick Calderoni, Daniel C. Kammer, R. Schmitt, C. Charman, E. Grabovsky, Charles W. Morrow, Craig L. Olson, M. Modesto, W. Szaroletta, S. Dean, H. Tran, R. Peterson, D. Oscar, D. Louie, William A. Stygar, R. Curry, M.A. Ulrickson, Susana Reyes, J F Latkowski, I.N. Sviatoslavsky, Dale Welch, James E. Bailey, J. S. De Groot, A. Kim, P. Panchuk, M.L. Kiefer, David L. Smith, H. Shatoff, J. P. VanDevender, M. E. Cuneo, J. P. Quintenz, M. Cipiti, C. Lascar, S. Nedoseev, R. Keith, Mark E. Barkey, S. A. Slutz, Jason Oakley, Dennis L. Sadowski, Kyle Robert Cochrane, C. Dillon, Mark Anderson, M. Walck, S.E. Rosenthal, W. Rickman, L.X. Schneider, Lalit C. Chhabildas, Ryan P. Abbott, Kenneth W. Struve, Joseph W. Schumer, V. Vigil, V. P. Smirnov, Said I. Abdel-Khalik, Alice Ying, Gregory A. Moses, S. Glover, Dillon H. McDaniel, T. W. L. Sanford, Maurice Keith Matzen, Ralph W. Moir, P.F. Ottinger, Gerald L. Kulcinski, N. Jensen, Wayne R. Meier, K. McDonald, A. S. Kingsep, K. Reed, Mohamed E. Sawan, E. Lindgren, Timothy D. Pointon, Cathy Ottinger Farnum, G. Pollock, Michael G. Mazarakis, Thomas Alan Mehlhorn, Neil Alexander, David Lester Hanson, Guy R. Bennett, P. Meekunasombat, L. Shephard, Richard E. Olson, Neil B. Morley, Laila El-Guebaly, V. Dandini, Gregory Rochau, Mark E. Savage, D. Schroen, Mohamed A. Abdou, Per F. Peterson, D. V. Rose, R. Gallix, W. Gauster, Matthew C. Turgeon, T. Tanaka, Timothy J. Renk, and J. D. Boyes
- Subjects
Physics ,Nuclear and High Energy Physics ,020209 energy ,Mechanical Engineering ,Nuclear engineering ,02 engineering and technology ,Fusion power ,01 natural sciences ,010305 fluids & plasmas ,Nuclear Energy and Engineering ,Z-pinch ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,General Materials Science ,Civil and Structural Engineering - Abstract
The long-range goal of the Z-Pinch IFE program is to produce an economically-attractive power plant using high-yield z-pinch-driven targets (~3GJ) with low rep-rate per chamber (~0.1 Hz). The prese...
- Published
- 2005
30. Towards a Modular Point Design for Heavy Ion Fusion
- Author
-
L. L. Chao, J.J. Barnard, Ronald C. Davidson, D. Callahan-Miller, L. Reginato, Simon S. Yu, Shmuel Eylon, J.W. Kwan, W.R. Meier, Per F. Peterson, Enrique Henestroza, Igor Kaganovich, Dale Welch, Aharon Friedman, Prabir K. Roy, Edward P. Lee, B.G. Logan, Matthaeus Leitner, D. V. Rose, W.L. Waldron, R.J. Briggs, and C.S. Debonnel
- Subjects
Nuclear and High Energy Physics ,020209 energy ,02 engineering and technology ,01 natural sciences ,Linear particle accelerator ,010305 fluids & plasmas ,law.invention ,Nuclear physics ,Optics ,law ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,General Materials Science ,Point (geometry) ,Civil and Structural Engineering ,Physics ,business.industry ,Mechanical Engineering ,Injector ,Fusion power ,Modular design ,Space charge ,Nuclear Energy and Engineering ,Pinch ,Physics::Accelerator Physics ,business ,Beam (structure) - Abstract
We report on an ongoing study on modular Heavy Ion Fusion (HIF) drivers. The modular driver is characterized by {approx}20 nearly identical induction linacs, each carrying a single high current beam. In this scheme, one of the full size induction linacs can be tested as an 'integrated Research Experiment' (IRE). Hence this approach offers significant advantages in terms of driver development path. For beam transport, these modules use solenoids, which are capable of carrying high line charge densities, even at low energies. A new injector concept allows compression of the beam to high line densities right after the source. The final drift compression is performed in a plasma in which the large repulsive space charge effects are neutralized. Finally, the beam is transversely compressed onto the target, using either external solenoids or current-carrying channels (in the assisted pinch mode of beam propagation). We report on progress towards a self-consistent point design from injector to target. Considerations of driver architecture, chamber environment as well as the methodology for meeting target requirements of spot size, pulse shape and symmetry are also described. Finally, some near-term experiments to address the key scientific issues are discussed.
- Published
- 2005
31. Overview of US heavy ion fusion research
- Author
-
Craig L. Olson, Patrick G. O'Shea, Ronald H. Cohen, R. A. Kishek, P. C. Efthimion, Dale Welch, Edward P. Lee, L. Prost, Alex Friedman, Irving Haber, L. R. Grisham, M. Kireeff Covo, David P. Grote, Matthaeus Leitner, Edward A. Startsev, Shmuel Eylon, Simon S. Yu, Wayne R. Meier, F.M. Bieniosek, J.J. Barnard, A.W. Molvik, Enrique Henestroza, Prabir K. Roy, B.G. Logan, Erik P. Gilson, Peter A. Seidl, Debra Callahan, W.L. Waldron, D. V. Rose, Christine M. Celata, J.-L. Vay, Hong Qin, Igor Kaganovich, S.M. Lund, J.W. Kwan, and Ronald C. Davidson
- Subjects
Physics ,Nuclear and High Energy Physics ,Particle accelerator ,Plasma ,Fusion power ,Condensed Matter Physics ,Linear particle accelerator ,Environmental Energy Technologies ,law.invention ,Nuclear physics ,law ,Quadrupole ,Physics::Accelerator Physics ,Thermal emittance ,Inertial confinement fusion ,Beam (structure) - Abstract
Significant experimental and theoretical progress has been made in the U.S. heavy ion fusion program on high-current sources, injectors, transport, final focusing, chambers and targets for high energy density physics (HEDP) and inertial fusion energy (IFE) driven by induction linac accelerators. One focus of present research is the beam physics associated with quadrupole focusing of intense, space-charge dominated heavy-ion beams, including gas and electron cloud effects at high currents, and the study of long-distance-propagation effects such as emittance growth due to field errors in scaled experiments. A second area of emphasis in present research is the introduction of background plasma to neutralize the space charge of intense heavy ion beams and assist in focusing the beams to a small spot size. In the near future, research will continue in the above areas, and a new area of emphasis will be to explore the physics of neutralized beam compression and focusing to high intensities required to heat targets to high energy density conditions as well as for inertial fusion energy.
- Published
- 2005
32. Chamber-transport simulation results for heavy-ion fusion drivers
- Author
-
D. V. Rose, Dale Welch, Simon S. Yu, Max Tabak, Debra Callahan, Per F. Peterson, and W.M. Sharp
- Subjects
Nuclear and High Energy Physics ,business.industry ,Nuclear engineering ,Particle accelerator ,Condensed Matter Physics ,law.invention ,Nuclear physics ,law ,Convergence (routing) ,Thermal emittance ,Electricity ,Engineering design process ,business ,Focus (optics) ,Cost of electricity by source ,Beam (structure) - Abstract
The heavy-ion fusion community recently developed a power-plant design that meets the various requirements of accelerators, final focus, chamber transport and targets. The point design is intended to minimize physics risk and is certainly not optimal for the cost of electricity. Recent chamber-transport simulations, however, indicate that changes in the beam ion species, the convergence angle and the emittance might allow more-economical designs.
- Published
- 2004
33. Repetitively pulsed, high energy KrF lasers for inertial fusion energy
- Author
-
D. Weidenheimer, Moshe Friedman, Matthew Wolford, S.B. Swanekamp, P. Kepple, John Giuliani, Frank Hegeler, T.C. Jones, Robert Lehmberg, M.C. Myers, John D. Sethian, and D. V. Rose
- Subjects
Nuclear and High Energy Physics ,Materials science ,business.industry ,Fusion power ,Pulsed power ,Condensed Matter Physics ,Laser ,Cathode ,Anode ,law.invention ,Optics ,law ,Cathode ray ,business ,Inertial confinement fusion ,Diode - Abstract
Krypton fluoride (KrF) lasers produce highly uniform beams at 248?nm, allow the capability of 'zooming' the spot size to follow an imploding pellet, naturally assume a modular architecture and have been developed into a pulsed-power-based industrial technology that readily scales to a fusion power plant sized system. There are two main challenges for the fusion power plant application: to develop a system with an overall efficiency of greater than 6% (based on target gains of 100) and to achieve a durability of greater than 3 ? 108 shots (two years at 5?Hz). These two issues are being addressed with the Electra (700?J, 5?Hz) and Nike (3000?J, single shot) KrF lasers at the Naval Research Laboratory. Based on recent advances in pulsed power, electron beam generation and transport, hibachi (foil support structure) design and KrF physics, wall plug efficiencies of greater than 7% should be achievable. Moreover, recent experiments show that it may be possible to realize long lived electron beam diodes using ceramic honeycomb cathodes and anode foils that are convectively cooled by periodically deflecting the laser gas. This paper is a summary of the progress in the development of the critical KrF technologies for laser fusion energy.
- Published
- 2004
34. Efficient electron beam deposition in the gas cell of the Electra laser
- Author
-
John D. Sethian, M.C. Myers, Frank Hegeler, D. V. Rose, Moshe Friedman, Matthew F. Wolford, and John Giuliani
- Subjects
Physics ,Argon ,Physics::Instrumentation and Detectors ,Krypton ,chemistry.chemical_element ,Condensed Matter Physics ,Laser ,Cathode ,law.invention ,Full width at half maximum ,chemistry ,law ,Cathode ray ,Deposition (phase transition) ,Atomic physics ,Inertial confinement fusion - Abstract
Extensive research has been performed to elucidate the transport of electron beam energy from a vacuum diode, through a foil support structure (hibachi), and into the Electra laser cell. Measurements and simulations of the energy deposition in the cell are reported for various krypton/argon mixtures, gas pressures, and the thickness and material of the hibachi foil. Two hibachi and several cathode configurations are investigated and electron energy deposition efficiencies into the gas of up to 75% have been achieved with a 500 kV, 180 ns full width at half maximum diode pulse. The experimental data are compared with one-, two-, and three-dimensional Monte Carlo transport calculations and particle-in-cell simulations. The importance of electron backscattering, radiation effects, and power deposition uniformity in the laser gas are discussed.
- Published
- 2004
35. Two-stream stability for a focusing charged particle beam
- Author
-
Dale Welch, T. C. Genoni, D. V. Rose, and Edward P. Lee
- Subjects
Physics ,Laplace transform ,Condensed Matter Physics ,Instability ,Charged particle ,Computational physics ,Spherical geometry ,symbols.namesake ,Classical mechanics ,Fourier transform ,Planar ,symbols ,Charged particle beam ,Beam (structure) - Abstract
The growth of the two-stream instability in one-dimensonal (1D) spherical geometry is analyzed using Laplace and Fourier transforms. An analytic expression for the asymptotic growth is obtained and compared to the well-known planar formula. Stronger linear growth is predicted for a converging beam than for its corresponding 1D planar counterpart at the same initial density. Calculations based on the analytic model are compared to 1D particle-in-cell simulations and excellent agreement is obtained.
- Published
- 2004
36. Operational Windows for Dry-Wall and Wetted-Wall IFE Chambers
- Author
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David A. Petti, John Perkins, R.W. Petzoldt, D. Haynes, L. Bromberg, J F Latkowski, A.R. Raffray, Simon S. Yu, D.T. Goodin, Craig L. Olson, Minami Yoda, Wayne R. Meier, W.M. Sharp, Dale Welch, L. El-Guebaly, Lester M. Waganer, P. Sharpe, Mark S. Tillack, Mofreh R. Zaghloul, Said I. Abdel-Khalik, S. Neff, R. L. Moore, D. V. Rose, and Farrokh Najmabadi
- Subjects
Nuclear and High Energy Physics ,Armour ,business.industry ,020209 energy ,Mechanical Engineering ,Buffer gas ,Process (computing) ,02 engineering and technology ,Fusion power ,Tracking (particle physics) ,01 natural sciences ,010305 fluids & plasmas ,Nuclear physics ,Nuclear Energy and Engineering ,0103 physical sciences ,Thermal ,0202 electrical engineering, electronic engineering, information engineering ,Pinch ,General Materials Science ,Aerospace engineering ,business ,Inertial confinement fusion ,Civil and Structural Engineering - Abstract
The ARIES-IFE study was an integrated study of inertial fusion energy (IFE) chambers and chamber interfaces with the driver and target systems. Detailed analysis of various subsystems was performed parametrically to uncover key physics/technology uncertainties and to identify constraints imposed by each subsystem. In this paper, these constraints (e.g., target injection and tracking, thermal response of the first wall, and driver propagation and focusing) were combined to understand the trade-offs, to develop operational windows for chamber concepts, and to identify high-leverage research and development directions for IFE research. Some conclusions drawn in this paper are (a) the detailed characterization of the target yield and spectrum has a major impact on the chamber; (b) it is prudent to use a thin armor instead of a monolithic first wall for dry-wall concepts; (c) for dry-wall concepts with direct-drive targets, the most stringent constraint is imposed by target survival during the injection process; (d) for relatively low yield targets (
- Published
- 2004
37. Electron beam pumped krypton fluoride lasers for fusion energy
- Author
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D. V. Rose, D. R. Welch, Matthew F. Wolford, Robert Lehmberg, S. Searles, R. V. Smilgys, D. Giorgi, M.C. Myers, S. P. Obenschain, Frank Hegeler, John Giuliani, Moshe Friedman, John D. Sethian, P. Kepple, S. B. Swanekamp, and D. Weidenheimer
- Subjects
Nike laser ,Materials science ,Excimer laser ,business.industry ,medicine.medical_treatment ,Laser science ,Fusion power ,Pulsed power ,Laser ,law.invention ,Optics ,law ,medicine ,Electrical and Electronic Engineering ,business ,Inertial confinement fusion ,Beam (structure) - Abstract
High-energy electron beam pumped krypton fluoride (KrF) gas lasers are an attractive choice for inertial fusion energy (IFE). Their short wavelength and demonstrated high beam uniformity optimizes the laser-target physics, and their pulsed power technology scales to a large system. This paper presents the principals of this type of laser and the progress toward developing technologies that can meet the IFE requirements for repetition rate (5 Hz), efficiency (>6%), and durability (>3/spl times/10/sup 8/ shots). The Electra laser at the Naval Research Laboratory (NRL) has produced >500 J of laser light in short 5-Hz bursts. Research on Electra and the NRL Nike laser (3000 J, single shot) has shown that the overall efficiency should be greater than 7%. This is based on recent advances in electron beam stabilization and transport, electron beam deposition, KrF laser physics, and pulsed power. The latter includes the development of a new solid-state laser triggered switch that will be the basis for a pulsed power system that can meet the IFE requirements for efficiency, durability, and cost. The major remaining challenge is to develop long-lived hibachi foils (e-beam transmission windows). Based on recent experiments, this may be achievable by periodically deflecting the laser gas.
- Published
- 2004
38. AGN Jet Interactions with the Intracluster Medium
- Author
-
J. H. Beall, J. Guillory, D. V. Rose, Sergio Colafrancesco, and Sabine Schindler
- Subjects
Physics ,Radio galaxy ,Astrophysics::High Energy Astrophysical Phenomena ,Astronomy ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Peculiar galaxy ,Galaxy groups and clusters ,Astrophysical jet ,Space and Planetary Science ,Intracluster medium ,Galaxy group ,Elliptical galaxy ,Astrophysics::Galaxy Astrophysics ,Galaxy cluster - Abstract
Clusters of galaxies contain large ellipticals near their cores. Elliptical galaxies in the centers of these clusters are often found to be the source of large-scale jets that propagate outward into the intracluster medium. These jets are thought to be produced by accretion-powered processes in the active galactic nuclei (AGN) at the centers of some giant ellipticals. In this paper, we discuss the origin of these jets and the likely consequences of their interactions with the intracluster medium in clusters of galaxies.
- Published
- 2003
39. Fusion energy with lasers, direct drive targets, and dry wall chambers
- Author
-
S. P. Obenschain, T.J. Tanaka, Elizabeth H. Stephens, J F Latkowski, Mark S. Tillack, Dale Welch, John Giuliani, J. Streit, Wayne R. Meier, Matthew Wolford, Robert R. Peterson, Farrokh Najmabadi, John H. Gardner, Gerald L. Kulcinski, Camille Bibeau, Craig L. Olson, Barry L. Freitas, Zoran Dragojlovic, L.J. Perkins, S.A. Payne, D. Geller, N. Ghoneim, D.T. Goodin, Robert Lehmberg, P. Kepple, D. Weidenheimer, S.B. Swanekamp, Timothy J. Renk, Gregory Rochau, James K. Hoffer, D. Haynes, Andrew J. Schmitt, Diana Grace Schroen, D. V. Rose, K. Skulina, A. Baraymian, Kathleen I. Schaffers, Raymond J. Beach, John D. Sethian, Lance Lewis Snead, R.W. Petzoldt, R. Raffray, G. Lucas, M.C. Myers, Moshe Friedman, Denis Colombant, and Frank Hegeler
- Subjects
Nuclear and High Energy Physics ,Fusion ,Materials science ,Fabrication ,business.industry ,Nuclear engineering ,Laser Inertial Fusion Energy ,Fusion power ,Condensed Matter Physics ,Laser ,Tracking (particle physics) ,law.invention ,Optics ,law ,business ,Batch production ,Diode - Abstract
A coordinated, focused effort is underway to develop Laser Inertial Fusion Energy. The key components are developed in concert with one another and the science and engineering issues are addressed concurrently. Recent advances include: target designs have been evaluated that show it could be possible to achieve the high gains (>100) needed for a practical fusion system.These designs feature a low-density CH foam that is wicked with solid DT and over-coated with a thin high-Z layer. These results have been verified with three independent one-dimensional codes, and are now being evaluated with two- and three-dimensional codes. Two types of lasers are under development: Krypton Fluoride (KrF) gas lasers and Diode Pumped Solid State Lasers (DPSSL). Both have recently achieved repetitive 'first light', and both have made progress in meeting the fusion energy requirements for durability, efficiency, and cost. This paper also presents the advances in development of chamber operating windows (target survival plus no wall erosion), final optics (aluminium at grazing incidence has high reflectivity and exceeds the required laser damage threshold), target fabrication (demonstration of smooth DT ice layers grown over foams, batch production of foam shells, and appropriate high-Z overcoats), and target injection (new facility for target injection and tracking studies).
- Published
- 2003
40. Assisted-pinched transport of heavy-ion beams in a fusion chamber
- Author
-
Bryan V. Oliver, Dale Welch, Craig L. Olson, T. C. Genoni, D. V. Rose, R. E. Clark, and Simon S. Yu
- Subjects
Nuclear reaction ,Physics ,Fusion ,business.industry ,Radius ,Condensed Matter Physics ,Magnetic field ,Ion ,Optics ,Physics::Plasma Physics ,Magnet ,Atomic physics ,business ,Inertial confinement fusion ,Beam divergence - Abstract
In heavy-ion inertial confinement fusion, ion beams are transported several meters through the reactor chamber to the target. This standoff distance mitigates damage to the final focus magnets and chamber walls from the target explosion. A promising transport scheme makes use of a preformed discharge channel to confine and guide the beams. In this assisted-pinched transport scheme, many individual beams are merged into two high-current beams for two-sided illumination of the fusion target. The beams are combined and focused outside the chamber before propagating at small radius in the discharge channel to the target. A large beam divergence can be contained by the strong magnetic field resulting from the roughly 50-kA discharge current. Using a hybrid particle-in-cell simulation code, we examine the dynamics of heavy-ion inertial confinement fusion driver-scale beams in this transport mode. Results from detailed two-dimensional simulations of assisted-pinched transport in roughly 1-Torr Xe suggest that th...
- Published
- 2003
41. Grad-B drift transport and focusing of high-current electron beams
- Author
-
J.W. Schumer, S.J. Stephanakis, R.J. Commisso, V. Chorny, S. Strasburg, P. F. Ottinger, D.D. Hinshelwood, and D. V. Rose
- Subjects
Physics ,business.industry ,Electron ,Radius ,Condensed Matter Physics ,Generator (circuit theory) ,Optics ,Cathode ray ,Physics::Accelerator Physics ,Laser beam quality ,High current ,Current (fluid) ,business ,Beam (structure) - Abstract
This paper studies, experimentally and theoretically, the grad-B drift transport and focusing of an intense electron beam. The Naval Research Laboratory’s Gamble II generator [J. D. Shipman, Jr., IEEE Trans. Nucl. Sci. NS-18, 243 (1971)] was used to drive a 900 kV, 850 kA beam. This beam drifted in the radial magnetic field gradient produced by an on-axis guide wire carrying a current of 40 kA. An additional axial magnetic field gradient generated by focusing spokes was used to radially compress the beam. Experimental diagnostics included radially resolved calorimetry and radiachromic film to study wall losses. Extensive simulations were performed to better understand the experiments. Energy transport efficiencies were slightly below 70%, and the focusing spokes were observed to compress the beam radius by approximately 10%.
- Published
- 2003
42. Electron beam pumped KrF lasers for fusion energy
- Author
-
John D. Sethian, S.B. Swanekamp, Moshe Friedman, Robert Lehmberg, D. Weidenheimer, Frank Hegeler, P. Kepple, Dale Welch, S. Searles, John Giuliani, S. P. Obenschain, Matthew F. Wolford, and D. V. Rose
- Subjects
Physics ,Nike laser ,business.industry ,Context (language use) ,Pulsed power ,Fusion power ,Condensed Matter Physics ,Laser ,law.invention ,Optics ,law ,Cathode ray ,Optoelectronics ,Laser beam quality ,business ,Inertial confinement fusion - Abstract
In this paper, we describe the development of electron beam pumped KrF lasers for inertial fusion energy. KrF lasers are an attractive driver for fusion, on account of their demonstrated very high beam quality, which is essential for reducing imprint in direct drive targets; their short wavelength (248 nm), which mitigates the growth of plasma instabilities; and their modular architecture, which reduces development costs. In this paper we present a basic overview of KrF laser technology as well as current research and development in three key areas: electron beam stability and transport; KrF kinetics and laser propagation; and pulsed power. The work will be cast in context of the two KrF lasers at the Naval Research Laboratory, The Nike Laser (5 kJ, single shot), and The Electra Laser (400–700 J repetitively pulsed).
- Published
- 2003
43. Progress in heavy ion fusion research
- Author
-
D. V. Rose, G.A. Westenskow, Ronald C. Davidson, F.M. Bieniosek, Ronald H. Cohen, Agust Valfells, Martin Reiser, Y. Zou, Dale Welch, Erik P. Gilson, Igor Kaganovich, Edward P. Lee, L. Prost, David P. Grote, John R. Harris, Hong Qin, Patrick G. O'Shea, Enrique Henestroza, Aharon Friedman, M. Walter, Christine M. Celata, W.L. Waldron, Grant Logan, B. Quinn, T.F. Godlove, J.J. Barnard, Y. Cui, Santiago Bernal, Donald W. Feldman, H. Li, S.M. Lund, Philip Efthimion, J.W. Kwan, Simon S. Yu, Edward A. Startsev, Irving Haber, L. R. Grisham, R. A. Kishek, Debra Callahan, A.W. Molvik, W.M. Sharp, Peter A. Seidl, and J.-L. Vay
- Subjects
Nuclear physics ,Physics ,law ,Plasma ,Ion trap ,Electron ,Injector ,Condensed Matter Physics ,Laser ,Beam (structure) ,law.invention ,Ion ,Perveance - Abstract
The U.S. Heavy Ion Fusion program has recently commissioned several new experiments. In the High Current Experiment [P. A. Seidl et al., Laser Part. Beams 20, 435 (2003)], a single low-energy beam with driver-scale charge-per-unit-length and space-charge potential is being used to study the limits to transportable current posed by nonlinear fields and secondary atoms, ions, and electrons. The Neutralized Transport Experiment similarly employs a low-energy beam with driver-scale perveance to study final focus of high perveance beams and neutralization for transport in the target chamber. Other scaled experiments—the University of Maryland Electron Ring [P. G. O’Shea et al., accepted for publication in Laser Part. Beams] and the Paul Trap Simulator Experiment [R. C. Davidson, H. Qin, and G. Shvets, Phys. Plasmas 7, 1020 (2000)]—will provide fundamental physics results on processes with longer scale lengths. An experiment to test a new injector concept is also in the design stage. This paper will describe th...
- Published
- 2003
44. Results from a scaled final focus experiment for heavy ion fusion
- Author
-
Peter A. Seidl, D. V. Rose, S.A. MacLaren, and A. Faltens
- Subjects
Physics ,Nuclear physics ,Ion beam ,Magnet ,Physics::Accelerator Physics ,Thermal emittance ,Focal Spot Size ,Electron ,Condensed Matter Physics ,Quadrupole magnet ,Beam (structure) ,Ion - Abstract
A one-tenth-scale version of a final focus subsystem for a heavy-ion-fusion driver has been built and used for experimental tests of concept. By properly scaling the parameters that relate ion energy and mass, current, emittance, and focusing fields, the transverse dynamics of a representative driver final focus have been replicated in a small laboratory beam. Whereas the driver beam parameters considered are 10 GeV Bi+ at 1.25 kA, the scaled experiment used a 95 μA beam of 160 keV Cs+ ions brought to a ballistic focus through a series of six quadrupole magnets. The measured focal spot size was consistent with calculations in the report of the design on which the experiment is based. In a second experimental program, a 400 μA beam was propagated through the focal system and partially neutralized after the last magnet using electrons released from a hot tungsten filament to test the predictions of the benefits of neutralization. The increase in beam current resulted in a corresponding increase in spot radi...
- Published
- 2002
45. Steady-state erosion of propagating ion beams
- Author
-
T. C. Genoni, Dale Welch, and D. V. Rose
- Subjects
Physics ,Steady state ,Proton ,Wave propagation ,Front (oceanography) ,Physics::Accelerator Physics ,Atomic physics ,Condensed Matter Physics ,Erosion (morphology) ,Charged particle beam ,Beam (structure) ,Ion ,Computational physics - Abstract
A steady-state analytic model of beam erosion is presented and compared with two-dimensional hybrid particle-in-cell simulations of 100 MeV to 2 GeV proton beams propagating in a dense background gas. The analytic model accounts for nonzero beam erosion front velocities and the finite energies of beam particles radially exiting the beam through a single parameter. The model is in agreement with the simulation results for a single value of this parameter over the beam energy ranges considered.A steady-state analytic model of beam erosion is presented and compared with two-dimensional hybrid particle-in-cell simulations of 100 MeV to 2 GeV proton beams propagating in a dense background gas. The analytic model accounts for nonzero beam erosion front velocities and the finite energies of beam particles radially exiting the beam through a single parameter. The model is in agreement with the simulation results for a single value of this parameter over the beam energy ranges considered.
- Published
- 2002
46. Comparison of particle-in-cell simulations and a wave-population model of electron-beam-plasma interactions
- Author
-
J. Guillory, D. V. Rose, and J. H. Beall
- Subjects
Physics ,Coupling ,Rate equation ,Plasma ,Condensed Matter Physics ,Computational physics ,Physics::Plasma Physics ,Physics::Space Physics ,Astrophysical plasma ,Particle-in-cell ,Atomic physics ,Stability Model ,Longitudinal wave ,Beam (structure) - Abstract
A spatially independent beam stability model [W. K. Rose et al., Astrophys. J. 280, 550 (1984)] is compared with one-dimensional particle-in-cell (PIC) simulations. The model uses rate equations to evaluate the coupling of longitudinal waves created by beam-plasma instabilities. Equilibrium solutions of the stability model are examined and wave energies from the model are compared with PIC simulations. The PIC simulations enable the stability model to be benchmarked and to explore the temporal evolution of the background plasma electron energy distribution, a capability not presently treated in the stability model. The generation of hot plasma electron tails is examined in the PIC simulations. The scalable, spatially independent model can be used in laboratory and astrophysical parameter regimes while numerical constraints limit the parameter regimes treatable in the PIC simulations.
- Published
- 2002
47. Particle-in-cell modeling for MJ scale dense plasma focus with varied anode shape
- Author
-
A. Link, E. C. Hagen, C. Halvorson, D. R. Welch, Andrea Schmidt, and D. V. Rose
- Subjects
Physics ,Debye sheath ,symbols.namesake ,Dense plasma focus ,Ion beam ,Pinch ,symbols ,Particle-in-cell ,Electron ,Plasma ,Atomic physics ,Anode - Abstract
Megajoule scale dense plasma focus (DPF) Z-pinches with deuterium gas fill are compact devices capable of producing 1012 neutrons per shot but past predictive models of large-scale DPF have not included kinetic effects such as ion beam formation or anomalous resistivity. We report on progress of developing a predictive DPF model by extending our 2D axisymmetric collisional kinetic particle-in-cell (PIC) simulations from the 4 kJ, 200 kA LLNL DPF to 1 MJ, 2 MA Gemini DPF using the PIC code LSP. These new simulations incorporate electrodes, an external pulsed-power driver circuit, and model the plasma from insulator lift-off through the pinch phase. To accommodate the vast range of relevant spatial and temporal scales involved in the Gemini DPF within the available computational resources, the simulations were performed using a new hybrid fluid-to-kinetic model. This new approach allows single simulations to begin in an electron/ion fluid mode from insulator lift-off through the 5-6 μs run-down of the 50+ c...
- Published
- 2014
48. Net current generation and beam transport efficiency of grad-B-drift transported relativistic electron beams
- Author
-
J.W. Schumer, P. F. Ottinger, D. V. Rose, and Dale Welch
- Subjects
Physics ,Range (particle radiation) ,Current generation ,chemistry ,Torr ,chemistry.chemical_element ,Electron ,Conductivity ,Current (fluid) ,Atomic physics ,Condensed Matter Physics ,Nitrogen ,Beam (structure) - Abstract
Numerical simulations of grad-B drifting, high-current, relativistic electron beams are presented. The simulations use a hybrid fluid/particle-in-cell code to study the net-current and conductivity evolution for 200 to 900 kA, 1.3 MeV annular electron beams in a background gas of nitrogen (N2) at pressures of 1–60 Torr. Optimum guide-wire current and gas pressure for efficient beam transport are found from the simulations to be ∼40 kA and ∼5–15 Torr of N2, respectively, with energy transport efficiencies as high as 80% for transport distances up to 200 cm. For beam currents and/or gas pressures near the high end of the ranges considered, large net currents significantly alter the magnetic-field profile and result in decreased transport efficiency. Transport efficiencies up to 90% are also found for a self-pinched transport mode in the 1–15 Torr N2 range with no wire current.
- Published
- 2001
49. Neutralization of an intense proton beam during transport in vacuum
- Author
-
D.D. Hinshelwood, Dale Welch, Jesse M. Neri, D. V. Rose, S.J. Stephanakis, B.V. Weber, P.F. Ottinger, and F.C. Young
- Subjects
Physics ,Nuclear and High Energy Physics ,Electron density ,Ion beam deposition ,Ion beam ,Proton ,Ballistic conduction ,Physics::Accelerator Physics ,Electron ,Atomic physics ,Instrumentation ,Beam (structure) ,Ion - Abstract
Neutralization of the ion beam during ballistic transport in the target chamber is an important issue for Heavy Ion Fusion (HIF). The Gamble II generator at NRL was used to inject a 100 kA, 1 MeV, 50 ns proton beam into a vacuum (∼10−4 Torr) transport region. High-sensitivity laser interferometry was used to measure the resulting electron density. Efficient beam transport is only possible for these beam parameters if electrons are extracted from the walls to provide a significant degree of charge and current neutralization. Complete neutralization could be obtained with an electron population co-moving with the ions and at the same density as the beam. The measured line-integrated electron density has the same time dependence and magnitude as the proton beam. A numerical simulation of the experimental arrangement produced results in reasonable agreement with the measurements.
- Published
- 2001
50. Self-pinched transport of an intense proton beam
- Author
-
Craig L. Olson, Dale Welch, S.J. Stephanakis, P. F. Ottinger, F. C. Young, B.V. Weber, D. Mosher, M.C. Myers, J. M. Neri, D. V. Rose, and D.D. Hinshelwood
- Subjects
Physics ,Electron density ,Ion beam ,Proton ,chemistry.chemical_element ,Electron ,Condensed Matter Physics ,chemistry ,Ionization ,Ballistic conduction ,Physics::Accelerator Physics ,Atomic physics ,Helium ,Beam (structure) - Abstract
Ion beam self-pinched transport (SPT) experiments have been carried out using a 1.1-MeV, 100-kA proton beam. A Rutherford scattering diagnostic and a LiF nuclear activation diagnostic measured the number of protons within a 5 cm radius at 50 cm into the transport region that was filled with low-pressure helium. Time-integrated signals from both diagnostics indicate self-pinching of the ion beam in a helium pressure window between 35 and 80 mTorr. Signals from these two diagnostics are consistent with ballistic transport at pressures above and below this SPT pressure window. Interferometric measurements of electron densities during beam injection into vacuum are consistent with ballistic transport with co-moving electrons. Interferometric measurements for beam injection into helium show that the electron density increases quadratically with pressure through the SPT window and roughly linearly with pressure above the SPT window. The ionization fraction of the helium plateaus at about 1.5% for pressures abov...
- Published
- 2000
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