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High frequency mode generation by toroidal Alfven eigenmodesMay 17 2019Nonlinear generation of high frequency mode (HFM) by toroidal Alfven eigenmode (TAE) observed in HL-2A tokamak is analyzed using nonlinear gyrokinetic theory. It is found that, the HFM can be dominated by $|nq-m|=1$ perturbations with predominantly ideal ... More

Tunable X-ray source by Thomson scattering during laser-wakefield accelerationMay 16 2019We report results on all-optical Thomson scattering intercepting the acceleration process in a laser wakefield accelerator. We show that the pulse collision position can be detected using transverse shadowgraphy which also facilitates alignment. As the ... More

A multi-physics methodology for four-states of matterMay 16 2019We propose a numerical methodology for the simultaneous numerical simulation of four states of matter; gas, liquid, elastoplastic solids and plasma. The distinct, interacting physical processes are described by a combination of compressible, inert and ... More

Thomson microwave scattering for electron number density diagnostics of miniature plasmas at low pressureMay 15 2019This work proposes a novel method of Thomson microwave scattering for electron number density measurements of miniature plasmas at pressures < 10 Torr. This method is applied to determine electron number density in a positive column of glow discharge ... More

Laser frequency upconversion in plasmas with finite ionization ratesMay 15 2019Laser frequency can be upconverted in a plasma undergoing ionization. For finite ionization rates, the laser pulse energy is partitioned into a pair of counter-propagating waves and static transverse currents. The wave amplitudes are determined by the ... More

Magnetic ionization-thermal instabilityMay 15 2019Linear analysis of the stability of diffuse clouds in the cold neutral medium with uniform magnetic field is performed. We consider that gas in equilibrium state is heated by cosmic rays, X-rays and electronic photoeffect on the surface of dust grains, ... More

From spirals to dwarf irregulars: a new tight scaling relation linking the gas and stellar content of galaxies to disc gravitational instabilityMay 14 2019We present a new galaxy scaling relation that predicts the mass fractions of atomic gas, molecular gas and stars as a function of fundamental physical properties such as mass and specific angular momentum. Our scaling relation stretches across two orders ... More

Verification of the global gyrokinetic stellarator code XGC-S for linear ion temperature gradient driven modesMay 14 2019XGC (X-point Gyrokinetic Code) is a whole-volume, total-f gyrokinetic particle-in-cell code developed for modelling tokamaks. In recent work, XGC has been extended to model more general 3D toroidal magnetic configurations, such as stellarators. These ... More

Terahertz Laser Combs in Graphene Field-Effect TransistorsMay 14 2019Electrically injected terahertz (THz) radiation sources are extremely appealing given their versatility and miniaturization potential, opening the venue for integrated-circuit THz technology. In this work, we show that coherent THz frequency combs in ... More

Rayleigh-Benard convection in a nonuniformly rotating electrically conductive medium in an external spiral magnetic fieldMay 14 2019The research is devoted to the stability of convective flow in a nonuniformly rotating layer of an electrically conducting fluid in a spiral magnetic field. The stationary and oscillatory modes of magnetic convection are considered depending on the profile ... More

Ballistic Injection and Acceleration of Positrons in the Laser-Plasma Bubble RegimeMay 13 2019A novel approach for positron injection and acceleration in laser driven plasma wakefield is proposed. A theoretical model is developed and confirmed through simulations. The proposal is based on employing two co-axially propagating beams ring-shaped ... More

Eliminating poor statistics in Monte-Carlo simulations of fast-ion losses to plasma-facing components and detectorsMay 13 2019With Wendelstein 7-X now up and running, and the construction of ITER proceeding, predicting fast-ion losses to sensitive plasma-facing components and detectors is gaining significant interest. A common recipe to perform such studies is to push a large ... More

Magnetic Helicity of Solar Wind Fluctuations at Ion-kinetic ScalesMay 13 2019We use magnetic helicity to characterise solar wind fluctuations at ion-kinetic scales. For the first time, we separate the contributions to helicity from fluctuations propagating at angles quasi-parallel and oblique to the local mean magnetic field, ... More

Similarity of magnetized plasma wake channels behind relativistic laser pulses with different wavelengthsMay 13 2019Using particle-in-cell simulations of relativistic laser plasma wakes in the presence of an external magnetic field, we demonstrate that there exists a parameter window where the dynamics of the magnetized wake channel are largely independent of the laser ... More

The nonmodal modified two-stream and ion-sound instabilities of a plasma with a sheared Hall currentMay 13 2019A new approach to the kinetic analysis of the instabilities driven by the Hall current with a sheared current velocity is presented. The developed theory predicts that in the Hall plasma with inhomogeneous electric field, the static spatial structure ... More

The nonmodal modified two-stream and ion-sound instabilities of a plasma with a sheared Hall currentMay 13 2019May 16 2019A new approach to the kinetic analysis of the instabilities driven by the Hall current with a sheared current velocity is presented. The developed theory predicts that in the Hall plasma with inhomogeneous electric field, the static spatial structure ... More

A stable semi-implicit algorithmMay 11 2019When the singular values of the evolution operator are all smaller or all greater than one, stable integration algorithms are obtained either by explicit or implicit methods. When the singular spectrum mixes greater and smaller than one values, neither ... More

Exact solution of two fluid plasma equations for the creation of jet-like flows and seed magnetic fields in cylindrical geometryMay 10 2019An exact solution of two fluid ideal classical plasma equations is presented which shows that the jet-like outflow and magnetic field are generated simultaneously by the density and temperature gradients of both electrons and ions. Particular profiles ... More

FLASHForward: Plasma-wakefield accelerator science for high-average-power applicationsMay 09 2019The FLASHForward experimental facility is a high-performance test-bed for precision plasma-wakefield research, aiming to accelerate high-quality electron beams to GeV-levels in a few centimetres of ionised gas. The plasma is created by ionising gas in ... More

Two-fluid simulations of waves in the solar chromosphere I: numerical code verificationMay 09 2019Solar chromosphere consists of a partially ionized plasma, which makes modeling the solar chromosphere a particularly challenging numerical task. Here we numerically model chromospheric waves using a two-fluid approach with a newly developed numerical ... More

Investigation of light ion fusion reactions with plasma dischargesMay 09 2019The scaling of reaction yields in light ion fusion to low reaction energies is important for our understanding of stellar fuel chains and the development of future energy technologies. Experiments become progressively more challenging at lower reaction ... More

The Generalized Nonlinear Ohm's Law: How a Strong Electric Field Influences Non-ideal MHD Effects in Dusty Protoplanetary DisksMay 08 2019The magnetohydrodynamics (MHD) of protoplanetary disks are strongly subject to the non-ideal MHD effects arising from the low ionization fraction of the disk gas. A strong electric field induced by gas motions can heat ionized gas particles and can thereby ... More

ViDA: a Vlasov-DArwin solver for plasma physics at electron scalesMay 08 2019We present a Vlasov-DArwin numerical code (ViDA) specifically designed to address plasma physics problems, where small-scale high accuracy is requested even during the non linear regime to guarantee a clean description of the plasma dynamics at fine spatial ... More

Reply to comment by Witte et al. on "Isochoric, isobaric, and ultrafast conductivities of aluminum, lithium,and carbon in the warm dense matter regime", Phys. Rev. E $96$, 053206 (2017)May 08 2019In Phys. Rev. E, $99$, 047201 (2019) Witte {\it et al.} have commented on our conductivity calculations [Phys. Rev. E $96$, 053206 (2017)] for warm dense matter (WDM). (i) They criticize our use of the spherically-averaged structure factor $S(k)$ for ... More

The effect of the stochasticity of photoionization on 3D streamer simulationsMay 07 2019Positive streamer discharges require a source of free electrons ahead of them for their growth. In air, these electrons are typically provided by photoionization. Here we investigate how stochastic fluctuations due to the discreteness of ionizing photons ... More

Application of the electromotive force as a shock front indicator in the inner heliosphereMay 07 2019The electromotive force (EMF) describes how the evolution and generation of a large-scale magnetic field is influenced by small-scale turbulence. Recent studies of in-situ measurements have shown a significant peak in the EMF while a coronal mass ejection ... More

Analytical solutions for nonlinear plasma waves with time-varying complex frequencyMay 07 2019We analytically examine the time evolution of plasma waves with time-varying complex frequency $\gamma - i \omega$ in the linear and nonlinear phases. Using a Laplace-like decomposition of the electric potential, we give allowed solutions for the time-varying ... More

Experimental Study of Ion Heating in Obliquely Merging Hypersonic Plasma JetsMay 06 2019In this experiment, we measure ion temperature evolution of collisional plasma shocks and colliding supersonic plasma flows across a range of species (Ar, Kr, Xe, N), Mach numbers, and collisionalities. Shocks are formed via the collision of discrete ... More

Minimizing betatron coupling of energy spread and divergence in laser-wakefield accelerated electron beamsMay 06 2019Matched beam loading in laser wakefield acceleration (LWFA), characterizing the state of flattening of the acceleration electric field along the bunch, leads to the minimization of energy spread at high bunch charges. Here, we demonstrate by independently ... More

Strong energy enhancement in a laser-driven plasma-based accelerator through stochastic frictionMay 06 2019Conventionally, friction is understood as an efficient dissipation mechanism depleting a physical system of energy as an unavoidable feature of any realistic device involving moving parts, e.g., in mechanical brakes. In this work, we demonstrate that ... More

Wakefield Excited by Ultrashort Laser Pulses in Near-Critical Density PlasmasMay 06 2019Laser wakefield acceleration (LWFA) using high repetition rate mJ-class laser systems brings unique opportunities for a broad range of applications. In order to meet the conditions required for the electron acceleration with lasers operating at lower ... More

ORB5: a global electromagnetic gyrokinetic code using the PIC approach in toroidal geometryMay 06 2019This paper presents the current state of the global gyrokinetic code ORB5 as an update of the previous reference [Jolliet et al., Comp. Phys. Commun. 177 409 (2007)]. The ORB5 code solves the electromagnetic Vlasov-Maxwell system of equations using a ... More

Numerical study of transition between even and odd toroidal Alfvén eigenmodes on EASTMay 06 2019Linear simulations of toriodal Alfv\'en eigenmodes (TAEs) driven by energetic particles (EPs) on EAST (Experimental Advanced Superconducting Tokamak) are performed using the hybrid-kinetic MHD (HK-MHD) model implemented in NIMROD code. The EAST equilibrium ... More

Analysis of fast turbulent reconnection with self-consistent determination of turbulence timescaleMay 04 2019We present results of Reynolds-averaged turbulence model simulation on the problem of magnetic reconnection. In the model, in addition to the mean density, momentum, magnetic field, and energy equations, the evolution equations of the turbulent cross-helicity ... More

Large-scale magnetic dynamos in non-helical and helical flows and a generalized quenching formalismMay 03 2019For ideal MHD, we analytically show that both helical and non-helical anisotropic velocity flows which dynamo amplify large-scale magnetic fields, also grow large-scale magnetic helicity. We then derive a new generalized quenching formalism for these ... More

Nonlinear wave interactions as a model for naturally enhanced ion-acoustic lines in the ionosphereMay 03 2019Incoherent radar scatter from the ionosphere will, for equilibrium conditions, show two symmetric ion-acoustic lines, one for each direction of wave propagation. Many observation, from the EISCAT Svalbard Radar (ESR) for instance, demonstrate that the ... More

The plasmoid instability in a confined solar flareMay 03 2019Eruptive flares (EFs) are associated with erupting filaments and, in some models, filament eruption drives flare reconnection. Recently, however, observations of a confined flare (CF) have revealed all the hallmarks of an EF (impulsive phase, flare ribbons, ... More

Experimental observation and simulation of the equilibration of electron swarms in a scanning drift tubeMay 03 2019We investigate the spatially and temporally resolved electron kinetics in a homogeneous electric field in argon gas, in the vicinity of an emitting boundary. This (transient) region, where the electron swarm exhibits non-equilibrium character with energy ... More

Particle-in-Cell Simulations of Density Peak Formation and Ion Acceleration from Short Pulse Laser-Driven Ponderomotive SteepeningMay 02 2019We use particle-in-cell (PIC) simulations and simple analytic models to investigate the laser-plasma interaction known as ponderomotive steepening. When normally incident laser light reflects at the critical surface of a plasma, the resulting standing ... More

Photon Acceleration in a Flying FocusApr 30 2019A high-intensity laser pulse propagating through a medium triggers an ionization front that can accelerate and frequency-upshift the photons of a second pulse. The maximum upshift is ultimately limited by the accelerated photons outpacing the ionization ... More

Summary of strong-field QED WorkshopApr 30 2019A workshop, "Probing strong-field QED in electron--photon interactions", was held in DESY, Hamburg in August 2018, gathering together experts from around the world in this area of physics as well as the accelerator, laser and detector technology that ... More

Variational average-atom model of electron-ion plasma with correlations and quantum bound electronsApr 30 2019In the present paper, we propose a variational average-atom model of electron-ion plasma performing a quantum treatment of bound electrons and accounting for correlations (VAAQBEC). This model addresses the correlation functions in a weakly-coupled plasma, ... More

Spin-polarization effects of an ultrarelativistic electron beam in an ultraintense two-color laser pulseApr 30 2019May 01 2019Spin-polarization effects of an ultrarelativistic electron beam head-on colliding with an ultraintense two-color laser pulse are investigated comprehensively in the quantum radiation-dominated regime. We employ a Monte Carlo method, derived from the recent ... More

Spin-polarization effects of ultrarelativistic electron beam in ultraintense two-color laser pulsesApr 30 2019Spin-polarization effects of an ultrarelativistic electron beam head-on colliding with ultraintense two-color laser pulses are investigated comprehensively in the quantum radiation-dominated regime. We employ a Monte Carlo method, derived from the recent ... More

Spin-polarization effects of an ultrarelativistic electron beam in an ultraintense two-color laser pulseApr 30 2019May 02 2019Spin-polarization effects of an ultrarelativistic electron beam head-on colliding with an ultraintense two-color laser pulse are investigated comprehensively in the quantum radiation-dominated regime. We employ a Monte Carlo method, derived from the recent ... More

Laser-Plasma Interactions Enabled by Emerging TechnologiesApr 30 2019An overview from the past and an outlook for the future of fundamental laser-plasma interactions research enabled by emerging laser systems.

Kinetic simulations of nonrelativistic perpendicular shocks of young supernova remnants. I. Electron shock-surfing accelerationApr 30 2019Electron injection at high Mach-number nonrelativistic perpendicular shocks is studied here for parameters that are applicable to young SNR shocks. Using high-resolution large-scale two-dimensional fully kinetic particle-in-cell (PIC) simulations and ... More

Theory of a cavity around a large floating sphere in complex (dusty) plasmaApr 30 2019In the last experiment with the PK-3 Plus laboratory onboard the International Space Station, interactions of millimeter-size metallic spheres with a complex plasma were studied~[M. Schwabe {\it et al.}, New J. Phys. {\bf 19}, 103019 (2017)]. Among the ... More

An asymptotic preserving well-balanced scheme for the isothermal fluid equations in low-temperature plasma applicationsApr 30 2019We present a novel numerical scheme for the efficient and accurate solution of the isothermal two-fluid (electron and ion) equations coupled to Poisson's equation for low-temperature plasmas. The model considers electrons and ions as separate fluids, ... More

Particle Heating and Energy Partition in Low-$β$ Guide Field Reconnection with Kinetic Riemann SimulationsApr 29 2019Kinetic Riemann simulations have been completed to explore particle heating during guide field reconnection in the low-$\beta$ environment of the inner heliosphere and the solar corona. The reconnection exhaust is bounded by two rotational discontinuities ... More

Spontaneous Transport Barriers Quench Turbulent Resistivity in 2D MHDApr 29 2019This Letter identifies the physical mechanism for the quench of turbulent resistivity in 2D MHD. Without an imposed, ordered magnetic field, a multi-scale, blob-and-barrier structure of magnetic potential forms spontaneously. Magnetic energy is concentrated ... More

CHNS: A case study of turbulence in elastic mediaApr 29 2019Recent progress in the study of Cahn-Hilliard Navier-Stokes (CHNS) turbulence is summarized. This is an example of \textit{elastic turbulence}, which can occur in elastic (i.e. self-restoring) media. Such media exhibit memory due freezing-in laws, as ... More

Non-Adiabatic Effects on Electron Beam Quality for Frequency-Tunable GyrotronsApr 29 2019May 06 2019We propose an unconventional electron gun structure in which the emitter is located on a concave cathode surface with a non-uniform electric field. Such a design violates the intuition that an emitter should place close to a uniform electric field to ... More

Non-Adiabatic Effects on Electron Beam Quality for Frequency-Tunable GyrotronsApr 29 2019Apr 30 2019We propose an unconventional electron gun structure in which the emitter is located on a concave cathode surface with a non-uniform electric field. Such a design violates the intuition that an emitter should place close to a uniform electric field to ... More

Non-Adiabatic Effects on Electron Beam Quality for Frequency-Tunable GyrotronsApr 29 2019We propose an unconventional electron gun structure in which the emitter is located on a concave cathode surface with a non-uniform electric field. Such a design violates the intuition that an emitter should place close to a uniform electric field to ... More

Intermediate shock substructures within a slow-mode shock occurring in partially ionised plasmaApr 29 2019Slow-mode shocks are important in understanding fast magnetic reconnection, jet formation and heating in the solar atmosphere, and other astrophysical systems. The atmospheric conditions in the solar chromosphere allow both ionised and neutral particles ... More

Ion-acoustic rogue waves in multi-ion plasmasApr 27 2019The basic properties of nonlinear ion-acoustic (IA) waves (IAWs), particularly finite amplitude IA rogue waves (IARWs) in a plasma medium (containing pair ions, iso-thermal positrons and non-thermal electrons) are theoretically investigated by deriving ... More

Ultrafast Polarization of an Electron Beam in an Intense Bi-chromatic Laser FieldApr 26 2019Here, we demonstrate the radiative polarization of high-energy electron beams in collisions with ultrashort pulsed bi-chromatic laser fields. Employing a Boltzmann kinetic approach for the electron distribution allows us to simulate the beam polarization ... More

Measured reduction in Alfvén wave energy propagating through longitudinal gradients scaled to match solar coronal holesApr 26 2019We have explored the effectiveness of a longitudinal gradient in Alfv\'en speed in reducing the energy of propagating Alfv\'en waves under conditions scaled to match solar coronal holes. The experiments were conducted in the Large Plasma Device at the ... More

A Frequency Filter of Backscattered Light of Stimulated Raman Scattering due to the Raman Rescattering in the Gas-filled HohlraumsApr 25 2019The coupling evolutions of stimulated Raman scattering (SRS) and Raman rescattering (re-SRS) are studied under the parameter conditions of relevance to the gas-filled hohlraum experiments at the National Ignition Facility by a nonenveloped fluid code ... More

Phase space dynamics of a plasma wakefield dechirper for energy spread reductionApr 25 2019Plasma-based accelerators have made impressive progress in recent years. However, the beam energy spread obtained in these accelerators is still at ~ 1 % level, nearly one order of magnitude larger than what is needed for challenging applications like ... More

FINMHD: an adaptive finite element code for magnetic reconnection and plasmoid chains formation in MagnetohydrodynamicsApr 25 2019Solving the problem of fast eruptive events in magnetically dominated astrophysical plasmas requires the use of particularly well adapted numerical tools. Indeed, the central mechanism based on magnetic reconnection is determined by a complex behavior ... More

Shear flow-interchange instability in nightside magnetotail causes auroral beads as a signature of substorm onsetApr 24 2019A geometric wedge model of the near-earth nightside plasma sheet is used to derive a wave equation for low frequency shear flow-interchange waves which transmit $\vec{E} \times \vec{B}$ sheared zonal flows along magnetic flux tubes towards the ionosphere. ... More

The X-ray Halo Scaling Relations of Supermassive Black HolesApr 24 2019We study the correlations between (direct) masses of supermassive black holes (SMBHs) and X-ray hot halo properties, by using a Bayesian analysis of archival datasets and theoretical models. We analyze fundamental and composite X-ray variables (plasma ... More

Simulating the Diverse Instabilities of Dust in Magnetized GasApr 23 2019Recently Squire & Hopkins showed that charged dust grains moving through magnetized gas under the influence of any external force (e.g. radiation pressure, gravity) are subject to a spectrum of instabilities. Qualitatively distinct instability families ... More

About stability of plasma in a magnetic fieldApr 22 2019The dynamics of the oscillator system is investigated. The conditions under which this dynamics becomes unstable are determined. In particular, it is shown that plasma in constant magnetic field becomes unstable if its density exceeds a certain critical ... More

Problematic nature of plasmoid theory of magnetic reconnectionApr 22 2019Plasmoid theory uses two-coordinate models to explain fast magnetic reconnection, which occurs on an Alfv\'enic, not a resistive time scale, in plasmas that are evolving in the near-ideal limit. The primary application has been to three-dimensional naturally-occurring ... More

Problematic nature of plasmoid theory of magnetic reconnectionApr 22 2019Apr 25 2019Plasmoid theory uses two-coordinate models to explain fast magnetic reconnection, which occurs on an Alfv\'enic, not a resistive time scale, in plasmas that are evolving in the near-ideal limit. The primary application has been to three-dimensional naturally-occurring ... More

Initializing anisotropic and unstable electron velocity distributions needed for investigating plasma kinetic instabilitiesApr 22 2019Plasmas with anisotropic electron velocity distribution functions are needed for the controlled study of kinetic plasma instabilities in the laboratory. We demonstrate that such plasma can be produced using ultrashort laser pulses via optical-field ionization ... More

Direct Observations of Traveling Ionospheric Disturbances as Focusers of Solar Radiation: Spectral CausticsApr 21 2019The solar radiation focusing effect is related to the specific phenomenon of propagation of the Sun-emitted HF and VHF waves through terrestrial ionosphere. This natural effect is observed with ground-based radio instruments running within 10-200 MHz ... More

An energy-conserving and asymptotic-preserving charged-particle orbit implicit time integrator for arbitrary electromagnetic fieldsApr 20 2019We present a new implicit asymptotic preserving time integration scheme for charged-particle orbit computation in arbitrary electromagnetic fields. The scheme is built on the Crank-Nicolson integrator and continues to recover full-orbit motion in the ... More

Global turbulence simulations of the tokamak edge region with GRILLIXApr 19 2019Turbulent dynamics in the scrape-off layer (SOL) of magnetic fusion devices is intermittent with large fluctuations in density and pressure. Therefore, a model is required that allows perturbations of similar or even larger magnitude to the time-averaged ... More

Mean Force Kinetic Theory: a Convergent Kinetic Theory for Weakly and Strongly Coupled PlasmasApr 19 2019A new closure of the BBGKY hierarchy is developed, which results in a convergent kinetic equation that provides a rigorous extension of plasma kinetic theory into the regime of strong Coulomb coupling. The approach is based on a single expansion parameter ... More

Plasma Wakefield Accelerator Research 2019 - 2040: A community-driven UK roadmap compiled by the Plasma Wakefield Accelerator Steering Committee (PWASC)Apr 19 2019The acceleration gradients generated in a laser- or beam-driven plasma wakefield accelerator are typically three orders of magnitude greater than those produced by a conventional accelerator, and hence plasma accelerators can open a route to a new generation ... More

Effects of hole-boring and relativistic transparency on particle acceleration in overdense plasma irradiated by short multi-PW laser pulsesApr 19 2019Propagation of short and ultra-intense laser pulses in a semi-infinite space of overdense hydrogen plasma is analyzed via fully-relativistic, real geometry particle-in-cell (PIC) simulations including radiation friction. The relativistic transparency ... More

Atomic Modeling of Photoionization Fronts in Nitrogen GasApr 18 2019Photoionization fronts play a dominant role in many astrophysical environments, but remain difficult to achieve in a laboratory experiment. Recent papers have suggested that experiments using a nitrogen medium held at ten atmospheres of pressure that ... More

Relativistic kinetic theory for spin-1/2 particles II: Conservation laws, thermodynamics, and linear wavesApr 18 2019We study a recently derived fully relativistic kinetic model for spin-1/2 particles. Firstly, the full set of conservation laws for energy, momentum and angular momentum are given, together with an expression for the (non-symmetric) stress-energy tensor. ... More

Magnetic field generation from a coil-shaped foil by a laser-triggered hot-electron currentApr 18 2019A strong electron current triggered by a femtosecond relativistically intense laser pulse in a foil coil-like target is shown to be able to generate a solenoidal-type extremely strong magnetic field. The magnetic field lifetime sufficiently exceeds the ... More

Collisionless Energy Transfer in Kinetic Turbulence: Field-Particle Correlations in Fourier SpaceApr 18 2019Turbulence is commonly observed in nearly collisionless heliospheric plasmas, including the solar wind and corona and the Earth's magnetosphere. Understanding the collisionless mechanisms responsible for the energy transfer from the turbulent fluctuations ... More

Particle Energy Diffusion in Linear Magnetohydrodynamic WavesApr 18 2019In high-energy astronomical phenomena, the stochastic particle acceleration by turbulences is one of promising processes to generate non-thermal particles. In this paper, providing a temporally evolving wave ensemble, which consists of a single mode (Alfv\'en, ... More

Theoretical Plasma PhysicsApr 17 2019These lecture notes were presented by Allan N. Kaufman in his graduate plasma theory course and a follow-on special topics course (Physics 242A, B, C and Physics 250 at the University of California Berkeley). The notes follow the order of the lectures. ... More

Theoretical Plasma PhysicsApr 17 2019Apr 28 2019These lecture notes were presented by Allan N. Kaufman in his graduate plasma theory course and a follow-on special topics course (Physics 242A, B, C and Physics 250 at the University of California Berkeley). The notes follow the order of the lectures. ... More

Variation of the transition energies and oscillator strengths for the 3C and 3D lines of the Ne-like ions under plasma environmentApr 17 2019We present the results of a detailed theoretical study which meets the spatial and temporal criteria of the Debye-Hu\"ckel (DH) approximation on the variation of the transition energies as well as the oscillator strengths for the ${2p^53d\ ^1P_1\rightarrow2p^6\ ... More

Role of magnetic field curvature in magnetohydrodynamic turbulenceApr 17 2019Magnetic field are transported and tangled by turbulence, even as they lose identity due to nonideal or resistive effects. On balance field lines undergo stretch-twist-fold processes. The curvature field, a scalar that measures the tangling of the magnetic ... More

Coherent diffraction radiation of relativistic terahertz pulses from a laser-driven micro-plasma-waveguideApr 16 2019We propose a method to generate isolated relativistic terahertz (THz) pulses using a high-power laser irradiating a mirco-plasma-waveguide (MPW). When the laser pulse enters the MPW, high-charge electron bunches are produced and accelerated to ~ 100 MeV ... More

Radiation beaming in the quantum regimeApr 16 2019Classical theories of radiation reaction predict that the electron motion is confined to the plane defined by the electron's instantaneous momentum and the force exerted by the external electromagnetic field. However, in the quantum radiation reaction ... More

Energy conversion in turbulent weakly-collisional plasmas: Eulerian Hybrid Vlasov-Maxwell simulationsApr 16 2019Kinetic simulations based on the Eulerian Hybrid Vlasov-Maxwell (HVM) formalism permit the examination of plasma turbulence with useful resolution of the proton velocity distribution function (VDF). The HVM model is employed here to study the balance ... More

Growth rates of the electrostatic waves in the upper-hybrid bandApr 16 2019The electrostatic waves with the frequencies close to the upper-hybrid frequency (the upper-hybrid band) are important for the generation of solar radio zebras. Considering the plasma composed from the thermal background plasma and hot and rare plasma ... More

Numerical study of tearing mode seeding in tokamak X-point plasmaApr 16 2019A detailed understanding of island seeding is crucial to avoid (N)TMs and their negative consequences like confinement degradation and disruptions. In the present work, we investigate the growth of 2/1 islands in response to magnetic perturbations. Although ... More

First experiments on Revolver shell collisions at the OMEGA LaserApr 15 2019Results of recent experiments on the OMEGA Laser are presented, demonstrating the ablator-driver shell collision relevant to the outer two shells of the Revolver triple-shell inertial-confinement-fusion concept [K. Molvig et al., PRL~{\bf 116}, 255003 ... More

Evolution of three-dimensional Relativistic Ion Weibel Instability: Competition with Kink InstabilityApr 15 2019In this paper, we report our recent findings on the relativistic Weibel instability and its nonlinear saturation by performing numerical simulations of collisionless plasmas. Analysis of the obtained numerical results revealed that the nonlinear phase ... More

A gyrokinetic model for the plasma periphery of tokamak devicesApr 15 2019A gyrokinetic model is presented that can properly describe strong flows, large and small amplitude electromagnetic fluctuations occurring on scale lengths ranging from the electron Larmor radius to the equilibrium perpendicular pressure gradient scale ... More

Envelope solitons in double pair plasmasApr 14 2019A double pair plasma system containing cold inertial positive and negative ions, and inertialess super-thermal electrons and positrons is considered. The standard nonlinear Schr\"{o}dinger equation is derived by using the reductive perturbation method ... More

An adjoint method for neoclassical stellarator optimizationApr 12 2019Stellarators are a promising route to steady-state fusion power. However, to achieve the required confinement, the magnetic geometry must be highly optimized. This optimization requires navigating high-dimensional ($N \sim 10^2$ parameters) spaces, often ... More

Isomorph invariance and thermodynamics of repulsive dense bi-Yukawa one-component plasmasApr 12 2019In numerous realizations of complex plasmas, dust-dust interactions are characterized by two screening lengths and are thus better described by a combination of Yukawa potentials. The present work investigates the static correlations and the thermodynamics ... More

Isomorph invariance and thermodynamics of repulsive dense bi-Yukawa one-component plasmasApr 12 2019Apr 30 2019In numerous realizations of complex plasmas, dust-dust interactions are characterized by two screening lengths and are thus better described by a combination of Yukawa potentials. The present work investigates the static correlations and the thermodynamics ... More

Cumulative whistler instability in fast solar winds: Constraints of electron temperature anisotropyApr 12 2019Context. Solar outflows are a considerable source of free energy which accumulates in multiple forms like beaming (or drifting) components and/or temperature anisotropies. However, kinetic anisotropies of plasma particles do not grow indefinitely and ... More

Single-shot determination of spin-polarization for ultrarelativistic electron beams via nonlinear Compton scatteringApr 11 2019Impacts of spin-polarization of an ultrarelativistic electron beam head-on colliding with a strong laser pulse on emitted photon spectra and electron dynamics have been investigated in the quantum radiation regime. We simulate photon emissions quantum ... More

HV discharges triggered by dual- and triple-frequency laser filamentsApr 11 2019We study the use of frequency upconversion schemes of near-IR picosecond laser pulses and compare their ability to guide and trigger electric discharges through filamentation in air. Upconversion, such as Second Harmonic Generation, is favorable for triggering ... More

Dynamics of electron beams in the solar corona plasma with density fluctuationsApr 11 2019The problem of beam propagation in a plasma with small scale and low intensity inhomogeneities is investigated. It is shown that the electron beam propagates in a plasma as a beam-plasma structure and is a source of Langmuir waves. The plasma inhomogeneity ... More