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Studying the dynamics of magnetic plasmas in the presence of pressure gradients, gravity, and Lorentz forces is essential for understanding wave generation and propagation in the solar atmosphere and other magnetic environments. Various solar phenomena, including sunspots, spicules, and coronal loops, are explored within these environments. We consider them as waveguides. These waveguides are interpreted as magnetic flux tubes, providing valuable information about wave properties. The dissipation of magnetohydrodynamic waves in hot coronal loops is investigated using a two-dimensional Cartesian model. The findings demonstrate a decrease in pulse amplitude, and dissipation or damping manifests across distinct segments of the magnetic flux tube as time progresses. We find that the considered viscosity in our model can accelerate the wave damping in the coronal loop, which is in agreement with the results reported by Ofman & Wang (2022). [ABSTRACT FROM AUTHOR]

This paper is presented to investigate the exact solutions to the modified Zakharov- Kuznetsov equation that have a critical role to play in mathematical physics. The tan (φ (ζ) /2)- expansion, (m + G'(ζ)/G(ζ))-expansion and He exponential function methods are used to reveal various analytical solutions of the model. The equation regulates the treatment of weakly nonlinear ion-acoustic waves in a plasma consisting of cold ions and hot isothermal electrons throughout the existence of a uniform magnetic field. Solutions in forms of W-shaped, singular, periodic-bright and bright are constructed. [ABSTRACT FROM AUTHOR]

We present rigorous analytical and computational models to study the plasma-waves in a gated-bilayer system present in a double-channel high electron mobility transistor. By analytically deriving the dispersion relations, we have identified the optical and acoustic modes in such systems. We find that the presence of the metal gate selectively modifies the optical plasmons of an ungatedbilayer, while the acoustic plasmons remain largely unchanged. Analysis shows that these modified optical plasmons could be advantageous for resonant and non-resonant plasma-wave devices. The paper further serves to verify our analytical formulae using a full-wave hydrodynamic numerical solver, based on finite difference time domain algorithm. Using the solver, we examine these modes in the gated/ungated bilayers under a plane wave excitation. We observe that, most incident power couples to the optical mode for such an excitation. Nevertheless, acoustic modes can also be excited, if the discontinuity dimensions are optimized accordingly. These observations are also explained using 2D field-plots for the first time, thus providing intuitive understanding of the plasmon excitation in the bilayers. [ABSTRACT FROM AUTHOR]

The direction of developing plasma magnetic control systems in D-shaped tokamaks with its actuality and scientific novelty is presented. Shortly the poloidal systems of ITER and DEMO are characterized. The new imitation computer digital platform for modeling plasma magnetic control systems in real time for application in physical experiments is described. The preliminary results of testing the plasma magnetic control system for the Globus-M2 tokamak (Ioffe Institute, S-Petersburg, Russia) on the target computer of the platform are given. The digital twin of the imitation platform is characterized. The methodology of risk minimization is presented. [ABSTRACT FROM AUTHOR]

The paper treats the methodology of the design and analysis of a tokamak plasma magnetic cascade multiloop control system with the example of the Globus-M spherical tokamak (Ioffe Institute, S-Petersburg, Russia) including a set of new features. The methodology covers: plasma equilibrium reconstruction based on the experimental data, derivation of linear plasma models relative to the reconstructed plasma equilibrium taking into account plasma diagnostics methods and equipment, development of a new original model of a thyristor current inverter as an actuator included in the system feedback, original multivariable cascade multiloop structure analysis by Relative Gain Array/ μ -procedures, and design of an H ∞ , multivariable plasma shape control system with adaptation of the magnetic axis position. • Plasma magnetic control system design methodology for elongated & spherical tokamaks. • Plasma equilibrium reconstruction & model derivations from tokamak experimental data. • Full thyristor current inverter model as a fast actuator for plasma position control. • Plasma H ∞ position, current & shape control system with adaptation of magnetic axis. • Plasma separatrix transition by feedback control system in the reachability region. [ABSTRACT FROM AUTHOR]

An analytical investigation of the combined effects of throughflow and magnetic field on the convective instability in an electrically conducting fluid layer, bounded in a Hele-Shaw cell is presented within the context of linear stability theory. The outcome of the important parameters on the stability of the system is examined analytically as well as graphically. It is observed that the throughflow and magnetic field have both stabilizing effects, while the Hele-Shaw number has a destabilizing effect on the behavior of the system. It is also found that the oscillatory mode of convection is possible only when the magnetic Prandtl number takes the values less than unity. [ABSTRACT FROM AUTHOR]

Abstract This work establishes a new regularity criterion for the 3D incompressible magneto-hydrodynamical (MHD) equations in terms of one directional derivative of the velocity (i.e., ∂ 3 u) on framework of the anisotropic Lebesgue spaces. More precisely, it is proved that if ∂ 3 u satisfies ∫ 0 T ‖ ‖ ∂ 3 u (τ) ‖ L x 3 α ‖ L x 1 x 2 β q d τ < + ∞ , where 2 q + 1 α + 2 β = k ∈ [ 1 , 3 2 ] and 3 k < α ≤ β ≤ 1 k − 1 , for some T > 0 , then the corresponding solution (u , b) to the 3D MHD equations is regular on (0 , T) × R 3. [ABSTRACT FROM AUTHOR]

Abstract An upgrade of the RFX-mod experiment is presently in the final design phase, aimed at widening the explored operational scenarios both in RFP and Tokamak configuration. The main design driver for this machine upgrade is the enhancement of the 'shell-plasma proximity', which is expected to provide a significant improvement in the plasma magnetic confinement. The achievement of this aim implies a major change of the internal components of the machine such as the removal of the present vacuum vessel, transferring the function of vacuum barrier to the duly modified toroidal support structure, and the integration of a new in-vessel support system to sustain the conductive stabilizing shell and the whole first wall. The paper presents an overview of the design choices and the proposed implementations, assessed on the base of engineering analyses and results of experimental tests performed on mock-ups of the new components. The solutions conceived to fulfill vacuum and electrical requirements of the in-vessel components, to guarantee their reliability during normal and abnormal operating conditions events, and interface compatibility with existing components and torus assembly sequence are finally highlighted. [ABSTRACT FROM AUTHOR]

In view of ITER operations, many experiments are being conducted on the EAST tokamak. In particular, new magnetic control approaches are being developed and need to be tested. In order to design and test a plasma current, position and shape control, an accurate modeling of EAST static equilibria and dynamic plasma evolution is required. Hence, a suite of simulation tools has been developed for the reconstruction of plasma equilibria, the generation of plasma linearized models and for the closed loop testing of magnetic control algorithms. These tools are meant to assess the reliability of such equilibria and models, in order to provide a robust tool for the purposes of control design. [ABSTRACT FROM AUTHOR]

Mechanisms of fast electron energy deposition in dense magnetized plasma are studied by hybrid particle-in-cell/fluid simulations. It is found that the energy deposition ratio of Ohmic heating and collisional heating can be enhanced significantly as an Al target is presented in a strongly axial magnetic field, attributed to the fast electrons rotating around the axial field. The weight of Ohmic heating is increased with laser intensity during ultraintense laser-driven fast electrons propagating both in magnetized and unmagnetized solid targets, which is the dominant heating mechanism as the laser intensity is greater than 1018 W/cm2 compared to the collisional heating. The degree of the axial magnetic field effect on the fast electron energy deposition mechanisms is dependent on target materials, which is much weaker for low-Z targets, such as CH2. The results here should be helpful for the target designing of fast electron applications. [ABSTRACT FROM AUTHOR]

Plasma turbulence is studied via direct numerical simulations in a two-dimensional spatial geometry. Using a hybrid Vlasov-Maxwell model, we investigate the possibility of a velocity-space cascade. A novel theory of space plasma turbulence has been recently proposed by Servidio et al. [Phys. Rev. Lett. 119, 205101 (2017)], supported by a three-dimensional Hermite decomposition applied to spacecraft measurements, showing that velocity space fluctuations of the ion velocity distribution follow a broad-band, power-law Hermite spectrum P(m), where m is the Hermite index. We numerically explore these mechanisms in a more magnetized regime. We find that (1) the plasma reveals spectral anisotropy in velocity space, due to the presence of an external magnetic field (analogous to spatial anisotropy of fluid and plasma turbulence); (2) the distribution of energy follows the prediction P ( m ) ∼ m − 2 , proposed in the above theoretical-observational work; and (3) the velocity-space activity is intermittent in space, being enhanced close to coherent structures such as the reconnecting current sheets produced by turbulence. These results may be relevant to the nonlinear dynamics weakly collisional plasma in a wide variety of circumstances. [ABSTRACT FROM AUTHOR]

The Rosetta orbiter witnessed several hundred diamagnetic cavity crossings (unmagnetized regions) around comet 67P/Churyumov-Gerasimenko during its two year survey of the comet. The characteristics of the plasma environment inside these diamagnetic regions are studied using in situ measurements by the Rosetta Plasma Consortium instruments. Although the unmagnetized plasma density has been observed to exhibit little dynamics compared to the very dynamical magnetized cometary plasma, we detected several localized dynamic plasma structures inside those diamagnetic regions. These plasma structures are not related to the direct ionization of local cometary neutrals. The structures are found to be steepened, asymmetric plasma enhancements with typical rising-to-descending slope ratio of ~2.8 (±1.9), skewness ~0.43 (±0.36), mean duration of ~2.7 (±0.9) min and relative density variation ΔN/N of ~0.5 (±0.2), observed close to the electron exobase. Similar steepened plasma density enhancements were detected at the magnetized boundaries of the diamagnetic cavity as well as outside the diamagnetic region. The plausible scalelength and propagation direction of the structures are estimated from simple plasma dynamics considerations. It is suggested that they are large-scale unmagnetized plasma enhancements, transmitted from the very dynamical outer magnetized region to the inner magnetic field-free cavity region. [ABSTRACT FROM AUTHOR]

Plasmoids, overdense blobs of plasma containing magnetic fields and high-energy particles, are a self-consistent outcome of the reconnection process in the relativistic regime. Recent two-dimensional particle-in-cell (PIC) simulations have shown that plasmoids can undergo a variety of processes (e.g. mergers, bulk acceleration, growth, and advection) within the reconnection layer. We developed a Monte Carlo code, benchmarked with the recent PIC simulations, to examine the effects of these processes on the steady-state size and momentum distributions of the plasmoid chain. The differential plasmoid size distribution is shown to be a power law, ranging from a few plasma skin depths to ~0.1 of the reconnection layer's length. The power-law slope is shown to be linearly dependent upon the ratio of the plasmoid acceleration and growth rates, which slightly decreases with increasing plasma magnetization. We perform a detailed comparison of our results with those of recent PIC simulations and briefly discuss the astrophysical implications of our findings through the representative case of flaring events from blazar jets. [ABSTRACT FROM AUTHOR]

A theoretical analysis of magnetic pressure effects in a magnetized liner inertial fusion-like plasma is presented. In previous publications [F. García-Rubio and J. Sanz, Phys. Plasmas 24, 072710 (2017)], the evolution of a hot magnetized plasma in contact with a cold unmagnetized plasma, aiming to represent the hot spot and liner, respectively, was investigated in planar geometry. The analysis was made in a double limit low Mach and high thermal to magnetic pressure ratio β. In this paper, the analysis is extended to an arbitrary pressure ratio. Nernst, Ettingshausen, and Joule effects come into play in the energy balance. The region close to the liner is governed by thermal conduction, while the Joule dissipation becomes predominant far from it when the pressure ratio is low. Mass ablation, thermal energy, and magnetic flux losses are reduced with plasma magnetization, characterized by the electron Hall parameter ω e τ e , until β values of order unity are reached. From this point forward, increasing the electron Hall parameter no longer improves the magnetic flux conservation, and mass ablation is enhanced due to the magnetic pressure gradients. A thoughtful simplification of the problem that allows to reduce the order of the system of governing equations while still retaining the finite β effects is presented and compared to the exact case. [ABSTRACT FROM AUTHOR]

We consider the problem of radiation from a traveling-wave antenna in a warm electron plasma which moves along a strong magnetic field at a constant velocity. To describe the electromagnetic properties of the plasma, we use the diagonal tensor of dielectric permittivity, which is calculated for a magnetized plasma with the Maxwellian electron velocity distribution allowing for collisions of electrons with neutral molecules. The dispersion relation is analyzed numerically, and expressions for the field amplitudes in the wave zone are obtained. The radiation resistance of the antenna is calculated. It is shown that as the phase velocity of the traveling current wave in the antenna approaches the average velocity of the plasma motion, the radiation field decreases exponentially with distance from the source as a result of the efficient transfer of the wave energy to the plasma electrons due to collisionless interaction. [ABSTRACT FROM AUTHOR]

We generalize the equations, which describe the backward-wave oscillator regime in the magnetized plasma in the presence of a jump (“step”) in the velocity distribution function of energetic charged particles, to the case of an arbitrary direction of the wave relative to an external magnetic field and an arbitrary wave mode. The dependence of instability threshold on the angle χ between the wave vector k and the external magnetic field B0 for whistler-mode waves and a slow extraordinary wave (Z-mode) is determined. [ABSTRACT FROM AUTHOR]

Abstracrt ITER is incorporating two types of In-Vessel Coils (IVCs): ELM Coils to mitigate Edge Localized Modes and VS Coils to provide a reliable Vertical Stabilization of the plasma. Strong coupling with the plasma is required in order that the ELM and VS Coils can meet their performance requirements. Accordingly, the IVCs are mounted on the Vacuum Vessel (VV) inner wall, in close proximity to the plasma, just behind the Blanket Shield Modules (BSM). Due to high radiation environment, mineral insulated copper conductors enclosed in a stainless steel jacket have been selected. The reference design and prototype work provided a good basis for the development of radiation resistant conductor capable of operating within the harsh conditions in ITER vacuum chamber. However, this effort identified shortcomings in achieving satisfactory manufacturing solution, and most significantly, difficulties in brazing the brackets onto the ELM coil conductor. Since this process has not proven successful, alternative designs are under development and prototyping. Prototype manufacturing on the alternative designs has been completed at ICAS, Italy and ASIPP, China. The aim was to eliminate the need for internal coil joints, to prove the principle of longer conductor length manufacturing, and to perform bending and welding trials on two different conductor cross-sections: circular and square. The procurement of the IVCs and their conductors will be done via direct call for tender from the ITER Organization. This paper will give an overview of the alternative design and prototype manufacturing of the ITER In-Vessel coils. [ABSTRACT FROM AUTHOR]

The EUROfusion Consortium develops a design of a fusion power demonstrator plant (DEMO) in the framework of the European “Horizon 2020” innovation and research program. One of the key components in the fusion reactor is the Breeding Blanket (BB) surrounding the plasma, ensuring tritium self-sufficiency, heat removal for conversion into electricity, and neutron shielding. Among the 4 candidates for the DEMO BB, 2 of them use helium as coolant (HCPB, HCLL), and another one (DCLL) uses helium to cool down the First Wall (FW) only. Due to uncertainties regarding the plasma Heat Flux (HF) load the DEMO BB integrated FW will have to cope with, a set of sensitive thermal and stress analyses have been performed in order to define the possible margin against HF the integrated Helium-Cooled Eurofer FW could have. Based on the Helium Cooled Lithium Lead (HCLL) equatorial outboard module dimensions, thermal and stress Finite Element Method analyses have been performed with Cast3M with various FW front wall thicknesses and HF, under normal steady state condition. Stress have been analyzed with RCC-MRx code including high temperature (creep), cyclic (fatigue) and irradiated rules. This paper shows that the thickness of the plasma-facing wall of the FW should be minimized, within the limits necessary to withstand primary stresses, in order to reduce the temperature on the structure and thus prevent fatigue and creep damage as well as a reduction of the stress limits Sm, function of temperature, to prevent ratcheting. Moreover, the paper will discuss the importance of having constant HF during the reactor operation. A small variation of HF could increase a lot the risk of damage such as fatigue and creep. At the end, the effect of irradiation shows up to be the limiting criterion and penalizes the capacity of the FW to withstand high HF. [ABSTRACT FROM AUTHOR]

We confirm the neutral-particle backflow characteristics of detached plasma with a Super-X divertor-like target using a linear divertor simulator TPD-Sheet IV. The effect of a divergent magnetic field upon the generation of the detached plasma is found to be weak. Under a divergent magnetic field, the heat load on the target plate with a Super-X divertor-like target is suggested to be reduced by 3–5 times compared with a case in which a conventional diverter (CD) is used. In addition, it is suggested that there is an optimal magnetic-field divergence that prevents backflow of neutral particles. [ABSTRACT FROM AUTHOR]

Molten layer characteristics were investigated for four W materials; pure W, W-10wt%Re, W-2wt%Ta and W with Al coating. Specimens were irradiated by a Nd:YAG laser (wavelength 1064 nm) simulating transient heat loads such as ELMs and disruption. The power density of the heat loads were varied in the 2.3–6.6 GW/m 2 range. Surface profiles were observed with a laser microscope. The central part of irradiated W-2wt%Ta became dented deeply in a wider range with increasing the power density in comparison with pure W and W-10wt%Re. This could be attributed to the release of Ta droplets by bumping (rapid boiling), closely related to microstructure and/or impurity concentration determined by the materials production processes. We also observed surface morphology changes of pure W with and without Al coating after irradiation in order to investigate the effect of the protective coatings. Melting of W with Al coating seems to be suppressed by a protective effect of Al film when compared with pure W. [ABSTRACT FROM AUTHOR]

The test facility ELISE (Extraction from a Large Ion Source Experiment) at IPP Garching, Germany, aims to demonstrate ITER-relevant negative ion beam parameters which are required for the NBI system of ITER. ELISE is equipped with a Radio Frequency driven source and an ITER‐like extraction system with half the ITER size. An H − or D − beam can be extracted for 10 s every 3 min from the continuously operating plasma source. The duration of the beam pulses is currently limited by the power supplies available at IPP. Although up to now record-setting 1 h plasmas have been produced in H − as well as in D − , long plasma pulse operation with multiple beam blips showed a key issue: the co-extracted electron current during the extraction phase is strongly dynamic and temporally instable, particularly in D − . These instabilities are likely caused by back-streaming positive ions and Cs dynamics in the source. In order to investigate the source physics in long beam pulses, an upgrade of ELISE using a steady state high voltage power supply is envisaged. This upgrade requires a new steady state diagnostic calorimeter for which a few concepts are being investigated, which make use of several thermocouples, IR thermography and water calorimetry to measure beam intensity, divergence, profile and homogeneity. In addition the suitability of a tungsten wire calorimeter to characterize the steady state beam is being examined. Shielding of delicate components in the beam line, e.g. a large DN 1250 mm gate valve, by means of suitable protection scrapers, is being considered. A selection of these technical solutions is presented and discussed in the paper. [ABSTRACT FROM AUTHOR]

The problem of time evolution of initial perturbation excited at the development of the Buneman instability (BI) in plasma with dissipation is solved. Developing fields are presented in the form of a wave train with slowly varying amplitude. It is shown that the evolution of the initial pulse in space and time is given by the differential equation of third order. The equation is solved and the expression for the asymptotic pulse shape is obtained. The expression gives the most complete information on the instability: the space-time distribution of the fields, growth rates, velocities of unstable perturbations, the influence of the collisions/dissipation on the instability, its character, (absolute/convective), etc. All these characteristics of the BI are carried out by analyzing the expression for the shape. The obtained results may be applied to any system in which the red-shifted electron stream oscillations resonantly interact with ions. Asymptotic shapes of the BI are presented for various levels of dissipation. [ABSTRACT FROM AUTHOR]

Laser pulse compression using magnetized resonance near the upper-hybrid frequency is promising for achieving higher output intensity in regimes previously thought impossible using unmagnetized plasmas. Using one dimensional particle-in-cell simulations, we verify that, by partially replacing plasma with an external transverse magnetic field of megagauss scale, the output pulse can be intensified by a factor of a few, due to the increased allowable amplification time despite a decreased growth rate. Further improvement is impeded by the generation of an electromagnetic wakefield, to which the amplified pulse loses more energy than it does in the unmagnetized case. This limitation can however be circumvented by the use of a stronger pump. In contrast to unmagnetized compression, the magnetized amplification remains efficient when the pump intensity is well above the wavebreaking threshold, until a higher phase-mixing threshold is exceeded. This surprising resilience to wavebreaking in magnetized plasma is of great benefit for magnetized compression. [ABSTRACT FROM AUTHOR]

The influence of quantum effects on the excitation of two instabilities, namely quantum dustacoustic and quantum dust-lower-hybrid waves due to the free streaming of ion/dust particles in uniformly magnetized dusty plasmas has been investigated using a quantum hydrodynamic model. We have obtained dispersion relations under some particular conditions applied on streaming ions and two contrastreaming dust particle beams at equilibrium and have analyzed the growth rates graphically. We have shown that with the increase of both the electron number density and the streaming speed of ion there is enhancement in the instability due to the fact that the dense plasma particle system with more energetic species having a high speed results in the increase of the growth rate in the electrostatic mode. The application of this work has been pointed out for laboratory as well as for space dusty plasmas. [ABSTRACT FROM AUTHOR]

We previously developed a tri-diagonalized finite-difference time-domain (FDTD) algorithm based on the weighted Laguerre polynomials (WLPs) for modeling wave propagation in magnetized plasma. The algorithm demonstrated dramatic CPU time reduction in comparison with the original WLP-FDTD algorithm. However, a splitting error was caused owing to the additional perturbation term. In this paper, an iterative scheme is introduced to the tri-diagonalized WLP-FDTD algorithm to further reduce the splitting error. Numerical example shows the accuracy and effectiveness of the proposed algorithm. [ABSTRACT FROM PUBLISHER]

The construction and operation of the JT-60SA tokamak is the main project currently carried out jointly by Japan and the European Union under the Broader Approach agreement. Within the Integrated Project Team, Japanese and European scientists are developing and testing a number of tools to support preliminary studies and future operations of JT-60SA. Within this collaborative framework, European scientists are using a set of assessed modeling tools to design and validate possible solutions for the plasma magnetic control system of JT-60SA. This paper introduces these tools and describes a possible control architecture to be used on the JT-60SA tokamak. The effectiveness of the proposed architecture is shown by means of numerical simulations. [ABSTRACT FROM AUTHOR]

Raman scattering of circularly polarized laser beams in a magnetized plasma channel is investigated. The scattering is considered as parametric instability. Dispersion relations of backward and forward scattered waves in a magnetized plasma are derived in a weakly relativistic regime. Growth rates of the corresponding instabilities are calculated. The effects of laser intensity and its polarization as well as the strength of the magnetic field and corresponding cyclotron frequency along with plasma density and its inhomogeneity on the growth rate of Raman scattering are examined. The study shows that the left-handed circularly polarized laser beam has different behaviors in comparison to the right-handed beam, and their growth rates are different due to the anisotropic properties of the magnetized plasma. In addition, Raman scattering in an inhomogeneous plasma with a linear density profile is investigated. The comparison between homogeneous and inhomogeneous plasmas has indicated that inhomogeneity reduces the growth rate. The frequency shift of scattered waves, when laser intensity is high, is studied in the magnetized plasma. The findings indicate that the shift depends on laser intensity and its polarization as well as plasma density and dc magnetic field. The frequency shift can be used as a diagnostic tool for density measurement in laser-plasma interactions. [ABSTRACT FROM AUTHOR]

Nonlinear Brillouin backward scattering of a linearly polarized short laser pulse propagating through a homogenous nonextensive distributed plasma in the presence of a uniform magnetic field perpendicular to both the direction of propagation and electric vector of the radiation field is investigated theoretically when ponderomotive relativistic and nonlinearity effects up to third order are taken into account. The governing equations for nonlinear wave in the context of nonextensive statistics are given, and the nonextensive coupled equations describing the nonlinear Brillouin backward scattering instability are solved by the Fourier transformation method, and the growth rate of the nonlinear Brillouin backward scattering instability is obtained. The results in the case q → 1 are consistent with those in the framework of the Maxwellian distribution. It is found that the instability growth rate increases on increasing plasma density, radiation field amplitude, and nonextensive parameter, while the instability growth rate shows a decrease due to the presence of external magnetic field. [ABSTRACT FROM AUTHOR]

The characteristics of magnetized capacitively coupled plasmas (CCPs) driven by combined dc/rf sources in argon have been investigated by a one-dimensional implicit Particle-in-cell/Monte Carlo collision model. Discharges operating at 13.56 MHz with a fixed rf voltage of 300 V are simulated at the pressure of 50 mTorr in argon. Four cases, i.e., CCP driven by rf source, rf + dc sources, rf source with magnetic field, and rf + dc sources with magnetic field, are presented and compared at the Vdc = -100 V, B = 50 Gs, and γi = 0.2. It is found that, with the influence of dc voltage and magnetic field, the plasma density has been greatly enhanced by over one order of magnitude over the rf-only case. This is due to the fact that the mean free path of electrons decreases by the cyclotron motion and the energetic secondary electrons are trapped by the magnetic field, leading to a significant increase in heating and ionization rates. Moreover, transition of the stochastic to Ohmic electron heating mechanism takes place as the magnetic field increases because electron kinetics can be strongly affected by the magnetic field. In general, we have demonstrated that such a configuration will enhance the discharge and thus enable CCPs work under extremely high energy density stably that can never be operated by any other configurations. We expect that such a configuration can promote many related applications, like etching, sputtering, and deposition. [ABSTRACT FROM AUTHOR]

A review was carried out on the exponentially permeable shrinking sheet and how it influenced the magnetohydrodynamic (MHD) mixed convection boundary layer flow of a Casson fluid. The boundary layer equations in the form of partial differential equations were transformed into the ordinary differential equations by using the similarity transformation. Subsequently, shooting technique is used to provide solutions for the ordinary differential equations. Different factors related to the flow and heat are indicated by the attained results as well as graphs. Moreover, 4 solutions are presented graphically. Also, the numerical calculations exhibit that the Casson fluid parameter, ϵ, buoyancy parameter, λ, and suction parameter, s, would significantly affect the characteristics of flow and thermal boundary layers of a Casson fluid. [ABSTRACT FROM AUTHOR]

Following the recent remarkable progress in magnetohydrodynamic (MHD) stability control in the C-2U advanced beam driven field-reversed configuration (FRC), turbulent transport has become one of the foremost obstacles on the path towards an FRC-based fusion reactor. Significant effort has been made to expand kinetic simulation capabilities in FRC magnetic geometry. The recently upgraded Gyrokinetic Toroidal Code (GTC) now accommodates realistic magnetic geometry from the C-2U experiment at Tri Alpha Energy, Inc. and is optimized to efficiently handle the FRC's magnetic field line orientation. Initial electrostatic GTC simulations find that ion-scale instabilities are linearly stable in the FRC core for realistic pressure gradient drives. Estimated instability thresholds from linear GTC simulations are qualitatively consistent with critical gradients determined from experimental Doppler backscattering fluctuation data, which also find ion scale modes to be depressed in the FRC core. Beyond GTC, A New Code (ANC) has been developed to accurately resolve the magnetic field separatrix and address the interaction between the core and scrape-off layer regions, which ultimately determines global plasma confinement in the FRC. The current status of ANC and future development targets are discussed. [ABSTRACT FROM AUTHOR]

Our understanding of laser-plasma instability (LPI) physics has improved dramatically over the past two decades through advancements in experimental techniques, diagnostics, and theoretical and modeling approaches. We have progressed from single-beam experiments-ns pulses with ∼kJ energy incident on hundred-micron-scale target plasmas with ∼keV electron temperatures-to ones involving nearly 2MJ energy in 192 beams onto multi-mm-scale plasmas with temperatures ∼4 keV. At the same time, we have also been able to use smaller-scale laser facilities to substantially improve our understanding of LPI physics and evaluate novel approaches to their control. These efforts have led to a change in paradigm for LPI research, ushering in an era of engineering LPI to accomplish specific objectives, from tuning capsule implosion symmetry to fixing nonlinear saturation of LPI processes at acceptable levels to enable the exploration of high energy density physics in novel plasma regimes. A tutorial is provided that reviews the progress in the field from the vantage of the foundational LPI experimental results. The pedagogical framework of the simplest models of LPI will be employed, but attention will also be paid to settings where more sophisticated models are needed to understand the observations. Prospects for the application of our improved understanding for inertial fusion (both indirect- and direct-drive) and other applications will also be discussed. Published by AIP Publishing. [ABSTRACT FROM AUTHOR]

A significant improvement of field reversed configuration (FRC) lifetime and plasma confinement times in the C-2 plasma, called High Performance FRC regime, has been observed with neutral beam injection (NBI), improved edge stability, and better wall conditioning [Binderbauer et al., Phys. Plasmas 22, 056110 (2015)]. A Quasi-1D (Q1D) fluid transport code has been developed and employed to carry out transport analysis of such C-2 plasma conditions. The Q1D code is coupled to a Monte-Carlo code to incorporate the effect of fast ions, due to NBI, on the background FRC plasma. Numerically, the Q1D transport behavior with enhanced transport coefficients (but with otherwise classical parametric dependencies) such as 5 times classical resistive diffusion, classical thermal ion conductivity, 20 times classical electron thermal conductivity, and classical fast ion behavior fit with the experimentally measured time evolution of the excluded flux radius, lineintegrated density, and electron/ion temperature. The numerical study shows near sustainment of poloidal flux for nearly 1ms in the presence of NBI. [ABSTRACT FROM AUTHOR]

The dispersion law and the anomalous magnetic moment of a neutrino in a magnetized electron-positron plasma are investigated as functions of the magnetic field strength, the polarization state, energy, direction of motion, and mass of the neutrino, and the parameters of the plasma. The calculation was performed by the method of the time Green's functions at finite temperature. Results for a massive neutrino in the limiting case are compared with the results of other authors, obtained earlier for a massless left-handed neutrino. [ABSTRACT FROM AUTHOR]

We extend previous analytical calculations of 2D high-β equilibria in order-unity aspect ratio tokamaks with toroidalflow to include pressureanisotropy, assuming guiding-center theory for a bi-Maxwellian plasma and the ideal MHD Ohm's law. Equilibrium solutions are obtained in the core region (which fills most of the plasma volume) and the boundary layer. We find that pressureanisotropy with p∥ > p⊥ (p∥ < p ⊥) reduces (enhances) the plasma diamagnetism relative to the isotropic case whenever an equilibrium solution exists. Sufficiently fast toroidalflows (Ω > Ωmin) were previously found to suppress the field-free region (diamagnetic hole) that exists in static isotropic high-β equilibria. We find that all equilibrium solutions with pressureanisotropy suppress the diamagnetic hole. For the static case with a volume-averaged toroidal beta of 70%, plasmas with max(p∥/p⊥)>α1=1.07max(p∥/p⊥)>α1=1.07 have equilibrium solutions. We find that α1 decreases with increasing toroidalflow speed, and above the flow threshold Ωmin we find α1=1, so that all p∥ > p⊥ plasmas have equilibrium solutions. On the other hand, for p∥ < p⊥ there are no equilibrium solutions below Ωmin. Above Ωmin (where there is no diamagnetic hole in the isotropic case), equilibrium solutions exist for α2 < min(p∥/p⊥) < 1, where α2 decreases from unity with increasing flow speed. The boundary layer width increases and the Shafranov shift decreases for p∥ > p⊥, while the converse is true for p∥ < p⊥. [ABSTRACT FROM AUTHOR]

In this paper, we discuss some questions related to the nature and manifestation of the equatorial electrojet. We study theoretically the equatorial electrojet as a nonlinear antenna for generating ultra-low-frequency electromagnetic signals during periodic heating of the ionosphere by the short-wave heater radiation. It is shown that for periodic heating at the frequency corresponding to the ULF band the generation of electromagnetic signals can be significantly intensified. This effect is especially important for the daytime magnetosphere where there are eigenfrequencies of the plasma magnetospheric maser in the electron radiation belts in the same frequency band. This can lead to a modification of VLF emissions in the subauroral magnetosphere. [ABSTRACT FROM AUTHOR]

The dispersion properties of surface dust ion-acoustic waves in a self-gravitating magnetized dusty plasma slab are investigated. The dispersion relation is derived by using the low-frequency magnetized dusty dielectric function and the surface wave dispersion integral for the slab geometry. We find that the self-gravitating effect suppresses the frequency of surface dust ion-acoustic wave for the symmetric mode in the long wavelength regime, whereas it hardly changes the frequency for the antisymmetric mode. As the slab thickness and the wave number increase, the surface wave frequency slowly decreases for the symmetric mode but increases significantly for the anti-symmetric mode. The influence of external magnetic field is also investigated in the case of symmetric mode. We find that the strength of the magnetic field enhances the frequency of the symmetric-mode of the surface plasma wave. The increase of magnetic field reduces the self-gravitational effect and thus the selfgravitating collapse may be suppressed and the stability of dusty objects in space is enhanced. [ABSTRACT FROM AUTHOR]

Dusty plasmas have been studied in argon, radio frequency (rf) glow discharge plasmas at magnetic fields up to 2.5 T where the electrons and ions are strongly magnetized. Plasmas are generated between two parallel plate electrodes where the lower, powered electrode is solid and the upper electrode supports a dual mesh consisting of #24 brass and #30 aluminum wire cloth. In this experiment, we study the formation of imposed ordered structures and particle dynamics as a function of magnetic field. Through observations of trapped particles and the quasi-discrete (i.e., "hopping") motion of particles between the trapping locations, it is possible to make a preliminary estimate of the potential structure that confines the particles to a grid structure in the plasma. This information is used to gain insight into the formation of the imposed grid pattern of the dust particles in the plasma. [ABSTRACT FROM AUTHOR]

Plasmas created by high-intensity lasers are often subject to the formation of kinetic-streaming instabilities, such as the Weibel instability, which lead to the spontaneous generation of high-amplitude, tangled magnetic fields. These fields typically exist on small spatial scales, i.e., "sub-Larmor scales." Radiation from charged particles moving through small-scale electromagnetic (EM) turbulence has spectral characteristics distinct from both synchrotron and cyclotron radiation, and it carries valuable information on the statistical properties of the EM field structure and evolution. Consequently, this radiation from laser-produced plasmas may offer insight into the underlying electromagnetic turbulence. Here, we investigate the prospects for, and demonstrate the feasibility of, such direct radiative diagnostics for mildly relativistic, solid-density laser plasmas produced in lab experiments. [ABSTRACT FROM AUTHOR]

The polarization characteristics of oblique incidence electromagnetic waves in magnetized cold plasma layer are studied using the finite-difference time-domain (FDTD) method based on the trapezoidal recursive convolution (TRC) technology. The TRC-FDTD formulations are derived in detail and are confirmed by computing the reflection and transmission coefficients for the elliptically polarized wave through a magnetized cold plasma slab with arbitrary magnetic direction. Particularly, when the propagation direction of the EM wave is parallel to the magnetic direction, the right-circular-polarized and left-circular-polarized wave should be considered. When the propagation direction of the EM wave is perpendicular to the magnetic direction, the ordinary polarized wave and extraordinary polarized wave should be considered. [ABSTRACT FROM PUBLISHER]