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Kinetic theory of linear fluctuations in magnetized and unmagnetized collisionfree plasmas

磁化和非磁化无碰撞等离子体线性波动的动力学理论

基本信息

批准号：
275578165
负责人：
Professor Dr. Reinhard Schlickeiser
金额：
--
依托单位：
Institut für Theoretische Physik IV: Weltraum- und Astrophysik
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2015
资助国家：
德国
起止时间：
2014-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/275578165?language=en
关键词：
Kinetic theory linear fluctuations magnetized

项目摘要

Fluctuations are a generic feature of all plasmas with finite random velocities of the plasma particles. Past research has concentrated predominantly on the fluctuations from collective weakly amplified/damped modes in the plasma using non-relativistic kinetic plasma equations. It is proposed to (1) extend the kinetic linear plasma fluctuation theory in unmagnetized plasmas calculating in particular the associated density and velocity fluctuation spectra of weakly propagating and weakly amplified/damped modes (collective and non-collective modes), and (2) develop the linear fluctuation theory for magnetized plasmas using the existing fluctuation theory of unmagnetized plasmas. These magnetized plasmas harbour an ordered magnetic field, uniform on spatial scales which are large compared to the wavelengths of the fluctuations. Due to the high conductivity of cosmic plasmas. no large-scale stationary electric fields exist in these systems. The most important unmagnetized cosmic plasma is the partially-ionized intergalactic medium (IGM) immediately after the reionization onset. The generation of aperiodic magnetic fluctuations in the IGM has been proposed by us as an important mechanism for the generation of cosmological seed magnetic fields. The associated turbulent density and velocity fluctuations can be used to place observational constraints on the strength of these fluctuations from dispersion measure, rotation measure and scintillation data as well as turbulent Doppler broadening of atomic and molecular lines, respectively. The general (with no restriction on the frequency of the fluctuations) kinetic linear fluctuation theory in magnetized plasmas using covariantly correct kinetic plasma equations has not been systematically studied before. The derivation of the generalized Kirchhoff laws for collective modes in magnetized plasmas allows us the quantitative calculation of the fluctuation intensities of electric and magnetic fields from collective modes for any given gyrotropic equilibrium plasma particle distribution $f_{a0}(\pper, \ppa )$ in magnetized plasmas, that take into account the effects of spontaneous emission and absorption. This permits in particular the quantitative modelling of the observed fluctuating magnetic field intensities in the solar wind plasma.

涨落是所有等离子体的一个普遍特征，等离子体粒子具有有限的随机速度。过去的研究主要集中在使用非相对论动力学等离子体方程的集体弱放大/阻尼模式的波动。本文建议（1）将动力学线性等离子体涨落理论推广到非磁化等离子体中，特别是计算弱传播和弱放大/阻尼模（集体模和非集体模）的密度和速度涨落谱;（2）利用现有的非磁化等离子体涨落理论发展磁化等离子体的线性涨落理论。这些磁化的等离子体拥有一个有序的磁场，在空间尺度上是均匀的，与波动的波长相比是很大的。因为宇宙等离子体的高传导性。在这些系统中不存在大规模的稳定电场。最重要的非磁化宇宙等离子体是再电离开始后立即部分电离的星系际介质（IGM）。IGM中非周期磁涨落的产生被认为是宇宙学种子磁场产生的一个重要机制。相关的湍流密度和速度波动可以用来放置这些波动的强度从色散测量，旋转测量和闪烁数据，以及湍流多普勒展宽的原子和分子线，分别观测约束。利用协变修正的等离子体动力学方程，对磁化等离子体中的一般动力学线性涨落理论（对涨落的频率没有限制）进行了系统的研究。导出了磁化等离子体集体模的广义基尔霍夫定律，定量计算了磁化等离子体中任意旋向性平衡粒子分布f_{a0}（\pper，\ppa）$的集体模电场和磁场的涨落强度，并考虑了自发辐射和吸收的影响.这特别允许在太阳风等离子体中观测到的波动磁场强度的定量建模。