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The effect of electrostatic microturbulence on fast particles rapidly decreases at high energy, but can be significant at moderate energy. Previous studies found that, in addition to changes in the energetic particle density, this results…

Plasma Physics · Physics 2018-12-26 George J. Wilkie

The observation that fast ions stabilize ion-temperature-gradient-driven microturbulence has profound implications for future fusion reactors. It is also important in optimizing the performance of present-day devices. In this work, we…

Plasma Physics · Physics 2018-06-06 George J. Wilkie , Aylwin Iantchenko , Ian G. Abel , Edmund Highcock , Istvan Pusztai

We investigate the ExB diffusion of fusion born \alpha particles in tokamak plasmas. We determine the transport regimes for a realistic model that has the characteristics of the ion temperature gradient (ITG) or of the trapped electron…

Plasma Physics · Physics 2017-02-01 A. Croitoru , D. I. Palade , M Vlad , F Spineanu

In a collisionless plasma, the energy distribution function of plasma particles can be strongly affected by turbulence. In particular, it can develop a non-thermal power-law tail at high energies. We argue that turbulence with initially…

Plasma Physics · Physics 2022-01-19 Cristian Vega , Stanislav Boldyrev , Vadim Roytershteyn , Mikhail Medvedev

The velocity-space distribution of alpha particles born in fusion devices is subject to modification at moderate energies due to turbulent transport. Therefore, one must calculate the evolution of an equilibrium distribution whose…

Plasma Physics · Physics 2016-06-22 George J. Wilkie , Ian G. Abel , Matt Landreman , William Dorland

Relativistic magnetically dominated turbulence is an efficient engine for particle acceleration in a collisionless plasma. Ultrarelativistic particles accelerated by interactions with turbulent fluctuations form non-thermal power-law…

Plasma Physics · Physics 2023-06-14 Cristian Vega , Stanislav Boldyrev , Vadim Roytershteyn

A central unresolved question in fusion energy research is whether energetic alpha particles, the primary products of deuterium-tritium fusion reactions, enhance or degrade plasma confinement. In burning plasmas, the operating regime of…

The slowing down of a charged particle beam passing through the dusty plasma with a non-thermal velocity alpha-distribution is studied. By using the Fokker-Planck collision theory, we derive the deceleration factor and slowing down time and…

Plasma Physics · Physics 2023-09-29 Yu Wang , Jiulin Du

Megaelectron volt (MeV) alpha particles will be the main source of plasma heating in magnetic confinement fusion reactors. Yet, instead of heating fuel ions, most of the energy of alpha particles is transferred to electrons. Furthermore,…

In the full-orbit particle simulations of energetic particle transport in plasmas, the plasma turbulence is typically described as a homogeneous superposition of linear Fourier modes. The turbulence evolution is, however, typically a…

Solar and Stellar Astrophysics · Physics 2012-04-03 Timo Laitinen , Silvia Dalla , James Kelly

We study stochastic acceleration models for the Fermi bubbles. Turbulence is excited just behind the shock front via Kelvin--Helmholtz, Rayleigh--Taylor, or Richtmyer--Meshkov instabilities, and plasma particles are continuously accelerated…

High Energy Astrophysical Phenomena · Physics 2015-11-10 Kento Sasaki , Katsuaki Asano , Toshio Terasawa

Fast ions have recently been found to significantly impact and partially suppress plasma turbulence both in experimental and numerical studies in a number of scenarios. Understanding the underlying physics and identifying the range of their…

Plasma Physics · Physics 2018-05-09 A. Di Siena , T. Görler , H. Doerk , R. Bilato , J. Citrin , T. Johnson , M. Schneider , E. Poli , JET Contributors

We construct the low-frequency formulation of the turbulence characterizing the plasma in a Tokamak edge. Under rather natural assumptions we demonstrate that, even in the presence of poloidal magnetic fluctuations, it is possible to deal…

Plasma Physics · Physics 2024-07-02 Giovanni Montani , Fabio Moretti

A challenging and fundamental research problem is the better understanding and control of the turbulent transport of heat in present-day tokamak fusion experiments. Recent developments in numerical methods along with enormous gains in…

Plasma Physics · Physics 2008-02-03 Jeremy Kepner , Scott Parker , Viktor Decyk

The author presents a model for variability of the flux and polarization of blazars in which turbulent plasma flowing at a relativistic speed down a jet crosses a standing conical shock. The shock compresses the plasma and accelerates…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Alan P. Marscher

Turbulent transport remains one of the principal obstacles to achieving efficient magnetic confinement in fusion devices. Two of the dominant drivers of the turbulence are microscale instabilities fuelled by electron- and ion-temperature…

In the context of global gyrokinetic simulations of turbulence using a Particle-In-Cell framework, verifying the delta-f assumption with a fixed background distribution becomes challenging when determining quasi-steady state profiles…

This work presents a model for generating nonthermal power-law tails of particles' energy probability density functions in turbulent collisionless plasmas, applicable to both non-relativistic and relativistic scenarios. We propose that…

Plasma Physics · Physics 2026-05-05 Stanislav Boldyrev , Daniel Humphrey , Vadim Roytershteyn

We analyze plasma heating in weakly collisional kinetic Alfv\'en wave (KAW) turbulence using high resolution gyrokinetic simulations spanning the range of scales between the ion and the electron gyroradii. Real space structures that have a…

Plasma Physics · Physics 2016-12-14 A. B. Navarro , B. Teaca , D. Told , D. Groselj , P. Crandall , F. Jenko

Turbulent high-energy astrophysical systems often feature asymmetric energy injection: for instance, Alfven waves propagating from an accretion disk into its corona. Such systems are "imbalanced": the energy fluxes parallel and…

High Energy Astrophysical Phenomena · Physics 2021-12-22 Amelia Hankla , Vladimir Zhdankin , Gregory Werner , Dmitri Uzdensky , Mitchell Begelman
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