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New cosmic ray transport effects from the mirror force in inhomogeneous magnetic fields

非均匀磁场中镜像力带来的新宇宙射线传输效应

基本信息

批准号：
248902482
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：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2016-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/248902482?language=en
关键词：
New cosmic ray transport effects

项目摘要

The parallel component of the mirror force in non-uniform large-scale guide magnetic fields gives rise to coherent convection of cosmic ray particles in particle position and momentum, referred to as adiabatic focusing and focused acceleration. Adiabatic focusing causes spatial particle streaming with a speed $\kapp /L$, given by the ratio of the parallel spatial diffusion coefficient and the focusing length $L$, along the guide field even in a medium at rest. Focused acceleration causes particle convection in momentum space, representing a 1st order Fermi particle acceleration mechanism for negative values of the product $H_cL<0$, where the cross helicity $H_c$ characterizes the excess of forward over backward moving plasma waves in the medium. Positive values of the cross helicity occur particularly in the upstream region of cosmic shock waves, because the upstream precursor distribution function of accelerated cosmic ray particles amplifies (damps) the forward- (backward-) propagating plasma waves. In a converging ($L<0$) guide magnetic field, as expected for the more than 70 galactic supernova remnants in close physical contact with massive molecular clouds, the efficient upstream focused acceleration can explain why they are efficient particle accelerators and strong emitters of high-energy GeV and TeV photons. It is proposed to improve the cosmic ray transport theory in the presence of focused transport and acceleration, provide new analytical solutions for the resulting time-dependent and stationary telegraph transport equation for realistic finite scattering regions, and to explore the favorable conditions for efficient particle acceleration in cosmic shock waves near massive molecular clouds. A further application is concerned with the explanation of the rising positron fraction in galactic cosmic rays.

非均匀大尺度引导磁场中镜像力的平行分量引起宇宙线粒子在粒子位置和动量上的相干对流，称为绝热聚焦和聚焦加速。绝热聚焦导致空间粒子流的速度为$\kapp /L$，由平行的空间扩散系数和聚焦长度$L$的比率给出，沿着引导场，即使在静止的介质中。聚焦加速引起动量空间中的粒子对流，代表一阶费米粒子加速机制，其中交叉螺旋度H_c表征介质中向前运动的等离子体波超过向后运动的等离子体波。正值的交叉螺旋度发生在宇宙冲击波的上游区域，特别是因为加速宇宙射线粒子的上游前体分布函数放大（阻尼）向前（向后）传播的等离子体波。在一个会聚的（$L<0$）引导磁场中，正如对70多个与大质量分子云密切物理接触的银河系超新星遗迹所预期的那样，有效的上游聚焦加速可以解释为什么它们是有效的粒子加速器和高能GeV和TeV光子的强发射体。提出了改进宇宙线输运理论中存在的聚焦传输和加速，提供新的解析解的时间相关的和固定的电报传输方程的现实有限的散射区域，并探讨有效的粒子加速的有利条件，在宇宙冲击波附近的大质量分子云。另一个应用是关于银河宇宙射线中正电子比例上升的解释。