arXiv: Plasma Physics最新文献_第3页

Preferential acceleration of positrons by a filamentation instability between an electron–proton beam and a pair plasma beam 电子-质子束和等离子体束之间的成丝不稳定性对正电子的优先加速

arXiv: Plasma Physics Pub Date : 2020-11-01 DOI: 10.1063/5.0021257

M. Dieckmann, S. Spencer, M. Falk, G. Rowlands

{"title":"Preferential acceleration of positrons by a filamentation instability between an electron–proton beam and a pair plasma beam","authors":"M. Dieckmann, S. Spencer, M. Falk, G. Rowlands","doi":"10.1063/5.0021257","DOIUrl":"https://doi.org/10.1063/5.0021257","url":null,"abstract":"Particle-in-cell (PIC) simulations of collisionless jets of electrons and positrons in an ambient electron-proton plasma have revealed an acceleration of positrons at the expense of electron kinetic energy. The dominant instability within the jet was a filamentation instability between electrons, protons and positrons. In this work we show that a filamentation instability, between an initially unmagnetized ambient electron-proton plasma at rest and a beam of pair plasma that moves through it at a non-relativistic speed, indeed results in preferential positron acceleration. Filaments form that are filled predominantly with particles with the same direction of their electric current vector. Positron filaments are separated by electromagnetic fields from beam electron filaments. Some particles can cross the field boundary and enter the filament of the other species. Positron filaments can neutralize their net charge by collecting the electrons of the ambient plasma while protons cannot easily follow the beam electron filaments. Positron filaments can thus be compressed to a higher density and temperature than the beam electron filaments. Filament mergers, which take place after the exponential growth phase of the instability has ended, lead to an expansion of the beam electron filaments, which amplifies the magnetic field they generate and induces an electric field in this filament. Beam electrons lose a substantial fraction of their kinetic energy to the electric field. Some positrons in the beam electron filament are accelerated by the induced electric field to almost twice their initial speed. The simulations show that a weaker electric field is induced in the positron filament and particles in this filament hardly change their speed.","PeriodicalId":8461,"journal":{"name":"arXiv: Plasma Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73569376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

A boundary value “reservoir problem” and boundary conditions for multi-moment multifluid simulations of sheaths 护套多矩多流体模拟的边值“储层问题”及边界条件

arXiv: Plasma Physics Pub Date : 2020-10-31 DOI: 10.1063/5.0024510

P. Cagas, A. Hakim, B. Srinivasan

引用次数: 2

Laser-Accelerated, Low-Divergence 15-MeV Quasimonoenergetic Electron Bunches at 1 kHz 激光加速，低发散15兆电子伏特准单能电子束在1千赫

arXiv: Plasma Physics Pub Date : 2020-10-29 DOI: 10.1103/PhysRevX.11.021055

F. Salehi, M. Le, L. Railing, M. Kolesik, H. Milchberg

引用次数: 18

Thermomagnetic instability of plasma composition gradients 等离子体组成梯度的热磁不稳定性

arXiv: Plasma Physics Pub Date : 2020-10-28 DOI: 10.1063/5.0027210

J. Sadler, Hui Li

引用次数: 1

Numerical scheme for evaluating the collision integrals for triple interactions in relativistic plasma 计算相对论等离子体中三重相互作用碰撞积分的数值格式

arXiv: Plasma Physics Pub Date : 2020-10-27 DOI: 10.1063/5.0022931

M. Prakapenia, I. Siutsou, G. Vereshchagin

引用次数: 2

Hydrodynamical model of QED cascade expansion in an extremely strong laser pulse 超强激光脉冲中QED级联膨胀的流体动力学模型

arXiv: Plasma Physics Pub Date : 2020-10-27 DOI: 10.1063/5.0035347

A. S. Samsonov, I. Kostyukov, E. Nerush

引用次数: 4

Reaching high laser intensity by a radiating electron 通过辐射电子达到高激光强度的

arXiv: Plasma Physics Pub Date : 2020-10-21 DOI: 10.1103/PhysRevA.103.053114

M. Jirka, P. Sasorov, S. Bulanov, G. Korn, B. Rus, S. V. Bulanov

引用次数: 2

Topology of the warm plasma dispersion relation at the second harmonic electron cyclotron resonance layer 二次谐波电子回旋共振层热等离子体色散关系的拓扑结构

arXiv: Plasma Physics Pub Date : 2020-10-16 DOI: 10.1063/5.0033880

P. L. Joostens, E. Westerhof

{"title":"Topology of the warm plasma dispersion relation at the second harmonic electron cyclotron resonance layer","authors":"P. L. Joostens, E. Westerhof","doi":"10.1063/5.0033880","DOIUrl":"https://doi.org/10.1063/5.0033880","url":null,"abstract":"The Warm Plasma Dispersion Relation, for waves in the electron cyclotron resonance range of frequencies, can be cast into the form of a bi-quadratic equation for $N_perp$, where the coefficients are a function of $N_perp^2$ and an iterative procedure is required to obtain a solution. However, this iterative procedure is not well understood and fails to converge towards a solution at the second harmonic resonance layer. In particular at higher densities where the wave can couple to an electron Bernstein wave. This paper focuses on a solution to the poor convergence of the iterative method, enabling determination of the topology of the dispersion relation around the second harmonic using a fully relativistic code for oblique waves. A feed-forward controller is proposed with the ability to adjust the rotation of a step of $N_perp^2$ within the complex plane, while also limiting the step-size. It is shown that implementation of the controller stabilizes unstable solutions, while improving overall robustness of the iteration. This allows the evaluation of the coupling between the fast extraordinary mode and electron Bernstein waves at the second harmonic electron cyclotron resonance layer, for non-perpendicularly propagating waves.","PeriodicalId":8461,"journal":{"name":"arXiv: Plasma Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83669567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Exact hybrid-kinetic equilibria for magnetized plasmas with shearing flows 剪切流磁化等离子体的精确混合动力学平衡

arXiv: Plasma Physics Pub Date : 2020-10-14 DOI: 10.1051/0004-6361/202039656

G. Guzzi, A. Settino, F. Valentini, F. Malara

{"title":"Exact hybrid-kinetic equilibria for magnetized plasmas with shearing flows","authors":"G. Guzzi, A. Settino, F. Valentini, F. Malara","doi":"10.1051/0004-6361/202039656","DOIUrl":"https://doi.org/10.1051/0004-6361/202039656","url":null,"abstract":"Context. Magnetized plasmas characterized by shearing flows are present in many natural contexts, such as the Earth's magnetopause and the solar wind. The collisionless nature of involved plasmas requires a kinetic description. When the width of the shear layer is of the order of ion scales, the Hybrid Vlasov-Maxwell approach can be adopted. Aims. The aim of the paper is to derive explicit forms for stationary configurations of magnetized plasmas with planar shearing flows,within the Hybrid Vlasov-Maxwell description. Two configurations are considered: the first with a uniform magnetic field obliquely directed with respect to the bulk velocity; and the second with a uniform-magnitude variable-direction magnetic field. Methods. Stationary ion distribution functions are obtained by combining single-particle constant of motions, which are derived studying particle dynamics. Preliminary information about the form of the distribution functions are analytically derived considering a local approximation for the background electromagnetic field. Then, a numerical method is set up to obtain a solution for general profiles. Results. The explicit distribution functions that are found allow to obtain profiles of density, bulk velocity, temperature and heat flux. Anisotropy and agyrotropy in the distribution function are also evaluated. Stationarity of the solution during numerical simulations is checked in the uniform oblique magnetic field case. Conclusions. The considered configurations can be used as models for the Earth's magnetopause in simulations of the Kelvin-Helmholtz instability.","PeriodicalId":8461,"journal":{"name":"arXiv: Plasma Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82031144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Non destructive testing of actively cooled plasma facing components by means of thermal transient excitation and infrared imaging. 热瞬态激发和红外成像技术在主动冷却等离子体表面构件无损检测中的应用。

arXiv: Plasma Physics Pub Date : 2020-10-06 DOI: 10.1016/B978-0-444-82762-3.50081-1

R. Mitteau, S. Berrebi, P. Chappuis, Ph. Darses, A. Dufayet, L. Garampon, D. Guilhem, M. Lipa, V. Martin, H. Roche

引用次数: 14