Generation and amplification of cosmic magnetic fields by kinetic plasma instabilities

动力学等离子体不稳定性产生和放大宇宙磁场

• 批准号: 84088448
• 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 Units
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/84088448?language=en
• 关键词: Generation; amplification; cosmic; magnetic; fields

The generation and amplification of weakly amplified and weakly propagating cosmic magnetic fields by kinetic instabilities of anisotropic particle distributions in fully and partially ionised plasmas is relevant for many cosmic sources including cosmological seed magnetic fields and powerful outflow sources such as solar flares, stellar and galactic winds, pulsar wind nebula, supernova shock waves and relativistic jets of active galactic nuclei and gamma-ray burst sources. The existence of magnetic fields is a mandatory requirement for the onset of nonthermal phenomena in such sources, that are well-established sources of high-energy photon radiation. Because in an appropriate frame of reference any cosmic outflow source can be modeled as counterstreaming plasmas, the magnetisation of such sources occurs by Weibel-type (in unmagnetised plasmas) and filamentation (in weakly magnetised plasmas) instabilities that generate aperiodic fluctuations in space which initially purely grow with time. Our investigations concentrate on the time evolution of such fluctuations, their saturation level, the influence of finite spatial extents of anisotropic plasmas, the role of associated transverse electric field fluctuations, and the calculation of scattering lengths and energy diffusion rates of plasma particles and energetic charged test particles.

完全和部分电离等离子体中各向异性粒子分布的动力学不稳定性产生和放大弱放大和弱传播的宇宙磁场与许多宇宙源相关，包括宇宙种子磁场和强大的外流源，例如太阳耀斑、恒星和银河风、脉冲星风星云、超新星冲击波和活动星系核的相对论喷流以及伽马射线爆发源。磁场的存在是这种源中非热现象发生的强制性要求，这种源是高能光子辐射的公认来源。因为在一个适当的参考系中，任何宇宙外流源都可以被建模为逆流等离子体，这些源的磁化通过韦伯型（在未磁化的等离子体中）和双折射（在弱磁化的等离子体中）不稳定性发生，这些不稳定性在空间中产生非周期性波动，最初纯粹是随着时间增长。我们的调查集中在这样的波动的时间演化，它们的饱和度，有限的空间范围的各向异性等离子体的影响，相关的横向电场波动的作用，以及等离子体粒子和高能带电测试粒子的散射长度和能量扩散率的计算。