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1. FUSE (Fusion Synthesis Engine): A Next Generation Framework for Integrated Design of Fusion Pilot Plants

Author

Meneghini, O., Slendebroek, T., Lyons, B. C., McLaughlin, K., McClenaghan, J., Stagner, L., Harvey, J., Neiser, T. F., Ghiozzi, A., Dose, G., Guterl, J., Zalzali, A., Cote, T., Shi, N., Weisberg, D., Smith, S. P., Grierson, B. A., and Candy, J.

Subjects
Physics - Plasma Physics
Abstract

The Fusion Synthesis Engine (FUSE) is a state-of-the-art software suite designed to revolutionize fusion power plant design. FUSE integrates first-principle models, machine learning, and reduced models into a unified framework, enabling comprehensive simulations that go beyond traditional 0D systems studies. FUSE's modular structure supports a hierarchy of model fidelities, from steady-state to time-dependent simulations, allowing for both pre-conceptual design and operational scenario development. This framework accelerates the design process by enabling self-consistent solutions across physics, engineering, and control systems, minimizing the need for iterative expert evaluations. Leveraging modern software practices and parallel computing, FUSE also provides multi-objective optimization, balancing cost, efficiency, and operational constraints. Developed in Julia, FUSE is fully open-source under the Apache 2.0 license, promoting transparency and collaboration within the fusion research community.

Published
2024

2. Characterization of the ELM-free Negative Triangularity Edge on DIII-D

Author

Nelson, A. O., Schmitz, L., Cote, T., Parisi, J. F., Stewart, S., Paz-Soldan, C., Thome, K. E., Austin, M. E., Scotti, F., Barr, J. L., Hyatt, A., Leuthold, N., Marinoni, A., Neiser, T., Osborne, T., Richner, N., Welander, A. S., Wehner, W. P., Wilcox, R., Wilks, T. M., and Yang, J.

Subjects
Physics - Plasma Physics
Abstract

Tokamak plasmas with strong negative triangularity (NT) shaping typically exhibit fundamentally different edge behavior than conventional L-mode or H-mode plasmas. Over the entire DIII-D database, plasmas with sufficiently negative triangularity are found to be inherently free of edge localized modes (ELMs), even at injected powers well above the predicted L-H power threshold. A critical triangularly ($\delta_\mathrm{crit}\simeq-0.15$), consistent with inherently ELM-free operation is identified, beyond which access to the second stability region for infinite-$n$ ballooning modes closes on DIII-D. It is also possible to close access to this region, and thereby prevent an H-mode transition, at weaker average triangularities ($\delta\lesssim\delta_\mathrm{crit}$) provided that at least one of the two x-points is still sufficiently negative. Enhanced low field side magnetic fluctuations during ELM-free operation are consistent with additional turbulence limiting the NT edge gradient. Despite the reduced upper limit on the pressure gradient imposed by ballooning stability, NT plasmas are able to support small pedestals and are typically characterized by an enhancement of edge pressure gradients beyond those found in traditional L-mode plasmas. Further, the pressure gradient inside of this small pedestal is unusually steep, allowing access to high core performance that is competitive with other ELM-free regimes previously achieved on DIII-D. Since ELM-free operation in NT is linked directly to the magnetic geometry, NT fusion pilot plants are predicted to maintain advantageous edge conditions even in burning plasma regimes, potentially eliminating reactor core-integration issues caused by ELMs.

Published
2024

3. First measurement using elliptically polarized photons of the double-polarization observable $E$ for $\gamma p \to p \pi^0$ and $\gamma p \to n \pi^+$

Author

A2 Collaboration, Afzal, F., Spieker, K., Hurck, P., Abt, S., Achenbach, P., Adlarson, P., Ahmed, Z., Akondi, C. S., Annand, J. R. M., Arends, H. J., Bashkanov, M., Beck, R., Biroth, M., Borisov, N., Braghieri, A., Briscoe, W. J., Cividini, F., Collicott, C., Costanza, S., Denig, A., Dieterle, M., Downie, E. J., Drexler, P., Fegan, S., Gardner, S., Ghosal, D., Glazier, D. I., Gorodnov, I., Gradl, W., Gurevich, D., Heijkenskjöld, L., Hornidge, D., Huber, G. M., Kashevarov, V. L., Kay, S. J. D., Korolija, M., Krusche, B., Lazarev, A., Livingston, K., Lutterer, S., MacGregor, I. J. D., Macrae, R. G., Manley, D. M., Martel, P. P., Miskimen, R., Mocanu, M., Mornacchi, E., Mullen, C., Neganov, A., Neiser, A., Oberle, M., Ostrick, M., Otte, P. B., Paudyal, D., Pedroni, P., Powell, A., Reicherz, G., Rostomyan, T., Sfienti, C., Sokhoyan, V., Steffen, O., Strakovsky, I. I., Strub, T., Supek, I., Thiel, A., Thiel, M., Thomas, A., Usov, Yu. A., Wagner, S., Walford, N. K., Watts, D. P., Werthmüller, D., Wettig, J., Witthauer, L., Wolfes, M., and Zachariou, N.

Subjects
Nuclear Experiment
Abstract

We report the measurement of the helicity asymmetry $E$ for the $p\pi^0$ and $n\pi^+$ final states using, for the first time, an elliptically polarized photon beam in combination with a longitudinally polarized target at the Crystal Ball experiment at MAMI. The results agree very well with data that were taken with a circularly polarized photon beam, showing that it is possible to simultaneously measure polarization observables that require linearly (e.g.~$G$) and circularly polarized photons (e.g.~$E$) and a longitudinally polarized target. The new data cover a photon energy range 270 - 1400 MeV for the $p\pi^0$ final state (230 - 842 MeV for the $n\pi^+$ final state) and the full range of pion polar angles, $\theta$, providing the most precise measurement of the observable $E$. A moment analysis gives a clear observation of the $p\eta$ cusp in the $p\pi^0$ final state.

Published
2024

4. Mindfulness-based intervention for depression and insulin resistance in adolescents: Protocol for BREATHE, a multisite, pilot and feasibility randomized controlled trial

Author

Sanchez, Natalia, Chen, Michele, Ho, Sally, Spinner, Holly, Vagadori, Jack, Neiser, Abigail, Padilla, Kimberly, Bristol, Madison, Winfield, Elijah, Thorstad, Isabel, Gulley, Lauren D., Lucas-Thompson, Rachel G., Pyle, Laura, Thompson, Talia, Estrada, Doris E., Basch, Molly, Tanofsky-Kraff, Marian, Kelsey, Megan M., Mackey, Eleanor R., and Shomaker, Lauren B.

Published
2024
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5. DIII-D research to provide solutions for ITER and fusion energy

Author

C.T. Holcomb, for the DIII-D Team:, J. Abbate, A. Abe, A. Abrams, P. Adebayo-Ige, S. Agabian, S. Ahmed, N. Aiba, N. Akcay, T. Akiyama, R. Albosta, P. Aleynikov, S. Allen, H. Anand, J. Anderson, Y. Andrew, M. Ashburn, A. Ashourvan, M. Austin, G. Avdeeva, D. Ayala, M. Ayub, E. Bagdy, S. Banerjee, K. Barada, L. Bardoczi, O. Bardsley, J. Barr, E. Bass, A. Battey, Z. Bayler, L. Baylor, T. Bechtel, M. Beidler, E. Belli, T. Benedett, Z. Bergstrom, M. Berkel, T. Bernard, N. Bertelli, R. Bielajew, G. Bodner, J. Boedo, R. Boivin, T. Bolzonella, P. Bonoli, A. Bortolon, S. Bose, M. Boyer, W. Boyes, L. Bradley, R. Brambila, A. Braun, D. Brennan, S. Bringuier, L. Brodsky, M. Brookman, J. Brooks, D. Brower, W. Brown, J. Buck, S. Buczek, D. Burgess, M. Burke, K. Burrell, J. Butt, R. Buttery, I. Bykov, P. Byrne, A. Cacheris, K. Callahan, J. Callen, D. Campbell, J. Candy, J. Canik, L. Cappelli, T. Carlstrom, R. Carr, W. Carrig, B. Carter, T. Carter, I. Carvalho, W. Cary, L. Casali, L. Ceelen, M. Cengher, M. Cha, R. Chaban, V. Chan, B. Chapman, I. Char, J. Chen, R. Chen, X. Chen, Y. Chen, J. Chiriboga, E. Cho, G. Choi, W. Choi, H. Choudhury, S. Chowdhury, C. Chrystal, Y. Chung, R. Churchill, R. Clark, M. Clement, J. Coburn, S. Coda, R. Coffee, C. Collins, J. Colmenares-Fernandez, W. Conlin, R. Coon, T. Cote, A. Creely, N. Crocker, C. Crowe, B. Crowley, T. Crowley, M. Curie, D. Curreli, A. Dal Molin, J. Damba, E. Dart, A. Dautt-Silva, K. Davda, A. De, N. de Boucaud, Y. de Jong, P. DE VRIES, A. de-Villeroche, G. DeGrandchamp, J. deGrassie, D. Demers, S. Denk, E. DeShazer, S. Di Genova, A. Diallo, A. Dimits, R. Ding, S. Ding, D. Donovan, X. Du, J. Dunsmore, A. Dupuy, J. Duran, A. Dvorak, F. Effenberg, N. Eidietis, D. Elder, D. Eldon, Y. Elsey, D. Ennis, K. Erickson, D. Ernst, M. Fajardo, H. Farre-Kaga, M. Fenstermacher, N. Ferraro, J. Ferron, A. Feyrer, P. Fimognari, R. Finden, D. Finkenthal, R. Fitzpatrick, S. Flanagan, B. Ford, W. Fox, S. Freiberger, L. Fu, K. Gage, V. Gajaraj, I. Garcia, F. Garcia, A. Garcia, M. Garcia Munoz, D. Garnier, A. Garofalo, A. Gattuso, B. Geiger, K. Gentle, Y. Ghai, K. Gill, F. Glass, P. Gohil, X. Gong, J. Gonzalez-Martin, Y. Gorelov, V. Graber, R. Granetz, C. Gray, C. Greenfield, B. Grierson, R. Groebner, W. Grosnickle, M. Groth, S. Gu, H. Guo, J. Guterl, W. Guttenfelder, R. Hager, S. Hahn, M. Halfmoon, J. Hall, V. Hall-Chen, F. Halpern, G. Hammett, X. Han, C. Hansen, E. Hansen, J. Hanson, M. Hanson, A. Harris, R. Harvey, S. Haskey, D. Hatch, W. Hayashi, A. Hayes, W. Heidbrink, J. Herfindal, J. Hicok, E. Hinson, T. Hisakado, C. Holcomb, C. Holland, L. Holland, E. Hollmann, A. Holm, I. Holmes, K. Holtrop, R. Hong, R. Hood, L. Horvath, S. Houshmandyar, N. Howard, E. Howell, W. Hu, Y. Hu, Q. Hu, Y. Huang, J. Huang, A. Huang, A. Hubbard, J. Hughes, D. Humphreys, J. Hurtado, A. Hyatt, K. Imada, V. Izzo, A. Jalalvand, S. Jardin, A. Jarvinen, Y. Jeon, H. Ji, X. Jian, L. Jian, Y. Jiang, C. Johnson, J. Johnson, M. Jones, S. Joung, P. Jouzdani, E. Jung, E. Kallenberg, R. Kalling, D. Kaplan, A. Kaptanoglu, D. Kellman, J. Kennedy, F. Khabanov, J. Kim, H. Kim, E. Kim, S. Kim, K. Kim, C. Kim, T. Kim, J. King, A. Kinsey, D. Kirk, D. Klasing, A. Kleiner, M. Knolker, M. Kochan, B. Koel, J. Koenders, M. Koepke, R. Kolasinski, E. Kolemen, E. Kostadinova, M. Kostuk, G. Kramer, R. Kube, N. Kumar, R. La Haye, F. Laggner, C. Lahban, H. Lan, R. Landry, R. Lantsov, L. Lao, C. Lasnier, C. Lau, R. Leccacorvi, J. Leddy, M. Lee, S. Lee, K. Lee, R. Lee, M. Lehnen, A. Leonard, E. Leppink, M. LeSher, J. Lestz, J. Leuer, N. Leuthold, G. Li, X. Li, Y. Li, L. Li, N. Li, Z. Li, D. Lin, Z. Lin, Y. Lin, E. Linsenmayer, J. Liu, D. Liu, C. Liu, Z. Liu, Y. Liu, A. Loarte-Prieto, S. Loch, L. LoDestro, N. Logan, J. Lohr, J. Lore, U. Losada Rodriguez, J. Loughran, M. Lowell, T. Luce, N. Luhmann, P. Lunia, R. Lunsford, L. Lupin-Jimenez, A. Lvovskiy, B. Lyons, X. Ma, J. MacDonald, T. Macwan, R. Maingi, M. Major, L. Malhotra, M. Margo, C. Marini, A. Marinoni, A. Maris, E. Martin, J. Mateja, R. Mattes, R. Maurizio, D. Mauzey, L. McAllister, G. McArdle, J. McClenaghan, K. McCollam, G. McKee, K. McLaughlin, A. McLean, V. Mehta, E. Meier, S. Meitner, J. Menard, O. Meneghini, G. Merlo, S. Messer, W. Meyer, C. Michael, D. Miller, M. Miller, J. Mitchell, E. Mitra, C. Moeller, M. Mohamed, S. Molesworth, K. Montes, S. Mordijck, S. Morosohk, A. Moser, D. Mueller, S. Munaretto, C. Murphy, C. Muscatello, R. Myers, A. Nagy, D. Nath, M. Navarro, R. Nazikian, T. Neiser, A. Nelson, P. Nesbet, F. Nespoli, P. Nguyen, D. Nguyen, R. Nguyen, J. Nichols, M. Nocente, L. Nuckols, R. Nygren, T. Odstrcil, M. Okabayashi, E. Olofsson, D. Orlov, D. Orozco, N. Osborne, T. Osborne, F. OShea, D. Pace, D. Packard, A. Pajares Martinez, C. Pakosta, C. Pan, M. Pandya, D. Panici, A. Pankin, Y. Park, J. Park, C. Parker, S. Parker, P. Parks, M. Parsons, S. Paruchuri, C. Paz-Soldan, T. Pederson, W. Peebles, B. Penaflor, E. Perez, L. Periasamy, R. Perillo, C. Petty, M. Pharr, D. Pierce, C. Pierren, S. Pierson, A. Pigarov, L. Pigatto, D. Piglowski, S. Pinches, R. Pinsker, R. Pitts, J. Pizzo, M. Podesta, Z. Popovic, M. Porkolab, Q. Pratt, G. Prechel, I. Pusztai, P. Puthan-Naduvakkate, J. Qian, X. Qin, O. Ra, T. Raines, K. Rakers, K. Rath, J. Rauch, C. Rea, R. Reed, A. Reiman, M. Reinke, R. Reksoatmodjo, Q. Ren, J. Ren, Y. Ren, M. Rensink, T. Rhodes, N. Richner, J. Ridzon, G. Riggs, J. Riquezes, P. Rodriguez Fernandez, T. Rognlien, G. Ronchi, L. Rondini, R. Rosati, A. Rosenthal, M. Ross, J. Rost, A. Rothstein, J. Roveto, J. Ruane, D. Rudakov, R. Rupani, G. Rutherford, S. Sabbagh, J. Sachdev, N. Sadeghi, A. Salmi, F. Salvador, B. Sammuli, C. Samuell, A. Sandorfi, C. Sang, D. Santa, J. Sarff, O. Sauter, H. Savelli, C. Schaefer, H. Schamis, J. Schellpfeffer, D. Schissel, L. Schmitz, O. Schmitz, P. Schroeder, K. Schultz, E. Schuster, F. Sciortino, F. Scotti, J. Scoville, A. Seltzman, J. Seo, J. Serrano, I. Sfiligoi, M. Shafer, R. Shapov, H. Shen, N. Shi, D. Shiraki, B. Short, R. Shousha, H. Si, C. Sierra, G. Sinclair, P. Sinha, G. Sips, C. Skinner, T. Slendebroek, J. Slief, R. Smirnov, S. Smith, D. Smith, G. Snoep, P. Snyder, W. Solomon, X. Song, A. Sontag, V. Soukhanovskii, D. Spong, J. Squire, G. Staebler, L. Stagner, T. Stange, P. Stangeby, E. Starling, S. Stewart, T. Stoltzfus-Dueck, S. Storment, E. Strait, D. Su, L. Sugiyama, P. Sun, Y. Sun, X. Sun, C. Sung, W. Suttrop, Y. Suzuki, R. Sweeney, B. Taczak, Y. Takemura, S. Tang, W. Tang, G. Tardini, D. Taussig, K. Teixeira, K. Thackston, D. Thomas, K. Thome, Y. Tinguely, M. Tobin, J. Tooker, A. Torrezan de Sousa, P. Traverso, G. Trevisan, E. Trier, D. Truong, C. Tsui, F. Turco, A. Turnbull, L. Turner, E. Unterberg, B. Van Compernolle, R. van Kampen, M. Van Zeeland, B. Victor, R. Vieira, E. Viezzer, S. Vincena, D. Vollmer, J. Wai, M. Walker, R. Waltz, W. Wampler, L. Wang, Y. Wang, H. Wang, Z. Wang, G. Wang, A. Wang, J. Watkins, M. Watkins, T. Watts, L. Webber, K. Weber, W. Wehner, X. Wei, D. Weisberg, A. Welander, A. Welsh, A. White, R. Wilcox, G. Wilkie, T. Wilks, M. Willensdorfer, H. Wilson, A. Wingen, M. Wu, D. Wu, S. Wukitch, J. Xia, R. Xie, Z. Xing, G. Xu, X. Xu, Z. Yan, X. Yang, L. Yang, S. Yang, J. Yang, M. Yoo, G. YU, J. Yu, A. Zalzali, A. Zamengo, V. Zamkovska, S. Zamperini, K. Zarrabi, E. Zeger, K. Zeller, L. Zeng, X. Zhang, J. Zhang, B. Zhang, B. Zhao, C. Zhao, Y. Zheng, Y. Zhu, J. Zhu, J. Ziegel, J. Zimmerman, and C. Zuniga

Subjects
DIII-D, tokamak, overview, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

The DIII-D tokamak has elucidated crucial physics and developed projectable solutions for ITER and fusion power plants in the key areas of core performance, boundary heat and particle transport, and integrated scenario operation, with closing the core-edge integration knowledge gap being the overarching mission. New experimental validation of high-fidelity, multi-channel, non-linear gyrokinetic turbulent transport models for ITER provides strong confidence it will achieve Q ⩾ 10 operation. Experiments identify options for easing H-mode access in hydrogen, and give new insight into the isotopic dependence of transport and confinement. Analysis of 2,1 islands in unoptimized low-torque IBS demonstration discharges suggests their onset time occurs randomly in the constant β phase, most often triggered by non-linear 3-wave coupling, thus identifying an NTM seeding mechanism to avoid. Pure deuterium SPI for disruption mitigation is shown to provide favorable slow cooling, but poor core assimilation, suggesting paths for improved SPI on ITER. At the boundary, measured neutral density and ionization source fluxes are strongly poloidally asymmetric, implying a 2D treatment is needed to model pedestal fuelling. Detailed measurements of pedestal and SOL quantities and impurity charge state radiation in detached divertors has validated edge fluid modelling and new self-consistent ‘pedestal-to-divertor’ integrated modeling that can be used to optimize reactors. New feedback adaptive ELM control minimizes confinement reduction, and RMP ELM suppression with sustained high core performance was obtained for the first time with the outer strike point in a W-coated, compact and unpumped small-angle slot divertor. Advances have been made in integrated operational scenarios for ITER and power plants. Wide pedestal intrinsically ELM-free QH-modes are produced with more reactor-relevant conditions, Low torque IBS with W-equivalent radiators can exhibit predator-prey oscillations in T _e and radiation which need control. High- β _P scenarios with q _min > 2, q _95 –7.9, β _N > 4, β _T –3.3% and H _98y2 > 1.5 are sustained with high density ( $\bar n$ = 7E19 m ^−3 , f _G –1) for 6 τ _E , improving confidence in steady-state tokamak reactors. Diverted NT plasmas achieve high core performance with a non-ELMing edge, offering a possible highly attractive core-edge integration solution for reactors.

Published
2024
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6. Successful prediction of tokamak transport in the L-mode regime

Author

G.M. Staebler, J.M. Park, E. Hassan, C. Angioni, E. Fable, C. Bourdelle, J.E. Kinsey, C. Holland, E.A. Belli, T. Neiser, J. Candy, and R.E. Waltz

Subjects
tokamak, turbulence, transport, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

A long standing shortfall in the predicted L-mode edge energy transport by reduced quasi-linear models of gyrokinetic turbulent transport has been resolved. The improved model TGLF-SAT2 has higher fidelity to gyrokinetic simulations of the electron-scale contribution to the electron energy transport and the ion-scale flux surface shape dependence of energy transport. The success of TGLF-SAT2 in predicting the L-mode and Ohmic edge profiles is critical to whole pulse simulation and opens the door to prediction of the H-mode power threshold.

Published
2024
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7. Understanding the L-H isotope effect at the DIII-D tokamak and advancements in synthetic turbulence diagnostics

Author

K.J. Callahan, L. Schmitz, Q. Pratt, T.A. Carter, G. Wang, H. Zhang, C. Holland, S.R. Haskey, A. Angulo, A. Bortolon, F. Effenberg, E.A. Belli, C. Chrystal, K.E. Thome, A. Ashourvan, T. Neiser, M. Knolker, F. Khabanov, Z. Yan, G.R. McKee, R. Chaban, R.S. Wilcox, A. Holm, F. Scotti, D. Truong, and R. Gerrú

Subjects
L-H transition, isotope, turbulence, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

It is determined that while heat flux differences between hydrogen and deuterium isotope experiments result from natural differences in carbon impurity content at DIII-D, it is not the origin of the low to high confinement mode (L-H) transition isotope effect. More specifically, a two times larger edge radial electric field in hydrogen compared to deuterium is uncovered and believed to play an important role. The origin of this radial electric field difference is determined to have two possible origins: differences in poloidal rotation and turbulent Reynolds stress in the closed field line region, and increased outer strike point temperatures and space potentials on open field lines. Experimental observations from both profile and turbulence diagnostics are supported by nonlinear gyrokinetic simulations using the code CGYRO. Simulations illustrated heat transport isotope effects in the plasma edge and shear layer resulting from differences in impurity content, electron non-adiabaticity, and main ion mass dependent E × B shear stabilization. Turbulence prediction comparisons from flux-matched CGYRO simulations to experimental measurements including electron temperature, density and velocity fluctuations are found to be in good agreement with available data. A dedicated DIII-D experiment in hydrogen was performed to seed more carbon than naturally occurring, to match deuterium experiments, and possibly reduce the L-H power threshold based on gyro-kinetic predictions. To our surprise, while ion temperature gradient (ITG) turbulence was stabilized, nodiscernible change in L-H power threshold were observed in these special hydrogen experiments. In particular, it is noticed that the edge radial electric field and Reynolds stress were observed as nearly unchanging in the presence of ITG stabilization. These experimental data have enabled a more comprehensive picture of the multitude of isotope effects at play in fusion experiments, and the important potential connection between the confined and unconfined plasma regions in regulating L-H transition dynamics.

Published
2024
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8. Pyrokinetics - A Python library to standardise gyrokinetic analysis

Author

Patel, Bhavin S., primary, Hill, Peter, additional, Pattinson, Liam, additional, Giacomin, Maurizio, additional, Bokshi, Arkaprava, additional, Kennedy, Daniel, additional, Dudding, Harry G., additional, Parisi, Jason. F., additional, Neiser, Tom F., additional, Jayalekshmi, Ajay C., additional, Dickinson, David, additional, and Ruiz, Juan Ruiz, additional

Published
2024
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10. Density wavenumber spectrum measurements, synthetic diagnostic development, and tests of quasilinear turbulence modeling in the core of electron-heated DIII-D H-mode plasmas.

Author

Pratt, Q., Hall-Chen, V., Neiser, T.F., Hong, R., Damba, J., Rhodes, T.L., Thome, K.E., Yang, J., Haskey, S.R., Cote, T., and Carter, T.

Subjects
PLASMA instabilities, WAVENUMBER, ELECTRON density, TURBULENCE, PLASMA turbulence, ELECTRON plasma, POWER spectra, TOROIDAL plasma
Abstract

Measurements of the turbulent density wavenumber spectrum, δ n ˆ e (k ⊥) , using the Doppler Back-Scattering (DBS) diagnostic are reported from DIII-D H-mode plasmas with electron cyclotron heating as the only auxiliary heating method. These electron-heated plasmas have low collisionality, ν e ∗ < 1 , T e / T i > 1 , and zero injected torque—a regime expected to be relevant for future fusion devices. We probe density fluctuations in the core (ρ ≈ 0.7) over a broad wavenumber range, 0.5 ⩽ k ⊥ ⩽ 16 cm−1 ( 0.1 ⩽ k ⊥ ρ s ⩽ 5), to characterize plasma instabilities and compare with theoretical predictions. We present a novel synthetic DBS diagnostic to relate the back-scattered power spectrum, P s (k ⊥) —which is directly measured by DBS—to the underlying electron density fluctuation spectrum, δ n ˆ e (k ⊥). The synthetic DBS P s (k ⊥) spectrum is calculated by combining the SCOTTY beam-tracing code with a model δ n ˆ e (k ⊥) predicted either analytically or numerically. In this work we use the quasi-linear code Trapped Gyro-Landau Fluid (TGLF) to approximate the δ n ˆ e (k ⊥) spectrum. We find that TGLF, using the experimental profiles, is capable of closely reproducing the DBS measurements. Both the DBS measurements and the TGLF-DBS synthetic diagnostic show a wavenumber spectrum with variable decay. The measurements show weak decay (k −0.6) for k < 3.5 cm−1, with k −2.6 at intermediate- k ( 3.5 ⩽ k ⩽ 8.5 cm−1), and rapid decay (k −9.4) for k > 8.5 cm−1. Scans of physics parameters using TGLF suggest that the normalized ∇ T e scale-length, R / L T e , is an important factor for distinguishing microturbulence regimes in these plasmas. A combination of DBS observations and TGLF simulations indicate that fluctuations remain peaked at ITG-scales (low k) while R / L T e -driven TEM/ETG-type modes (intermediate/high k) are marginally sub-dominant. [ABSTRACT FROM AUTHOR]

Published
2024
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11. Embolization of intercostal and lumbar arteries in advance of open surgery for Type II thoracoabdominal aneurysms

Author

Rodríguez Lecoq, Rafael, Barnés Navarro, Daniel, Pérez Lafuente, Mercedes, Zebdi, Naoufal, Rios Barrera, Remedios, Cuéllar Calabria, Hug, Rodríguez Palomares, José, Romero, Fiorella, Denadal, Miriam, Castro Alba, Miguel-Angel, Sureda-Barbosa, Carlos, Siliato, Mariasol, Palmer, Neiser, Vigil-Escalera López, Carlota, and Iorlano Mariano, Pier

Abstract

Open surgery for thoracoabdominal aortic aneurysms remains one of the most aggressive procedures, with a risk of paraplegia reaching up to 20% in some series. Preconditioning of the spinal circulation through prior embolization has been postulated to improve outcomes. We evaluate our initial experience with six patients.

Published
2024
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12. First Measurement Using Elliptically Polarized Photons of the Double-Polarization Observable E for γp→pπ^{0} and γp→nπ^{+}.

Author

Afzal F, Spieker K, Hurck P, Abt S, Achenbach P, Adlarson P, Ahmed Z, Akondi CS, Annand JRM, Arends HJ, Bashkanov M, Beck R, Biroth M, Borisov N, Braghieri A, Briscoe WJ, Cividini F, Collicott C, Costanza S, Denig A, Dieterle M, Downie EJ, Drexler P, Fegan S, Gardner S, Ghosal D, Glazier DI, Gorodnov I, Gradl W, Gurevich D, Heijkenskjöld L, Hornidge D, Huber GM, Kashevarov VL, Kay SJD, Korolija M, Krusche B, Lazarev A, Livingston K, Lutterer S, MacGregor IJD, Macrae RG, Manley DM, Martel PP, Miskimen R, Mocanu M, Mornacchi E, Mullen C, Neganov A, Neiser A, Oberle M, Ostrick M, Otte PB, Paudyal D, Pedroni P, Powell A, Reicherz G, Rostomyan T, Sfienti C, Sokhoyan V, Steffen O, Strakovsky II, Strub T, Supek I, Thiel A, Thiel M, Thomas A, Usov YA, Wagner S, Walford NK, Watts DP, Werthmüller D, Wettig J, Witthauer L, Wolfes M, and Zachariou N

Abstract

We report the measurement of the helicity asymmetry E for the pπ^{0} and nπ^{+} final states using, for the first time, an elliptically polarized photon beam in combination with a longitudinally polarized target at the Crystal Ball experiment at MAMI. The results agree very well with data that were taken with a circularly polarized photon beam, showing that it is possible to simultaneously measure polarization observables that require linearly (e.g., G) and circularly polarized photons (e.g., E) and a longitudinally polarized target. The new data cover a photon energy range 270-1400 MeV for the pπ^{0} final state (230-842 MeV for the nπ^{+} final state) and the full range of pion polar angles, θ, providing the most precise measurement of the observable E. A moment analysis gives a clear observation of the pη cusp in the pπ^{0} final state.

Published
2024
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