Cosmological magnetic field generation by the Weibel instability

导致星系间介质磁化的过程尚不清楚。宇宙中的大尺度结构，如细丝和星系片，是由最初密度过大的区域的引力坍缩演变而来的，产生了完全电离的气体物质的强烈相对运动和强烈的气体激波结构。提出了在星系际介质中由于涉及互穿电子流的威贝尔不稳定性而可能产生磁场的条件。由于星系间介质的高温，对维贝尔不稳定性的研究将基于现有的线性波的协变正确色散理论，从而大大改进了现有文献中的非相对论性处理方法。这些原始威贝尔磁场可以作为宇宙源中更强磁场的宇宙种子场。磁场的存在是宇宙源中大多数非热现象发生的必要条件，特别是伽马射线暴源和相对论性喷流源。根据目前的理解，星系中心的相对论性喷流的形成是由超大质量黑洞的吸积所驱动的，这是由于旋转吸积盘产生的快速超阿尔夫尼MHD风造成的，其中固定在吸积盘上的磁场对喷流的准直至关重要。当一个较快的风超过较慢的风时，就会形成相对论性磁化激波，通过扩散激波加速和随后的多普勒光束和超光速非热辐射成分，引起带电粒子的强烈加速。研究我们宇宙的非热历史与对宇宙磁化过程的理解密切相关。

The processes leading to the magnetization of the intergalactic medium are not yet known. Large-scale structures in the universe, like filaments and sheets of galaxies, evolve by the gravitational collapse of initially overdense regions giving rise to an intense relative motion of fully ionized gaseous matters and strong gaseous shock structures. It is proposed to investigate the conditions under which magnetic fields in the intergalactic medium may be generated due to the Weibel-type instabilities involving interpenetrating electron streams. Because of the hot temperatures of the intergalactic medium the investigation of the Weibel instability will be based on the now available covariantly correct dispersion theory of linear waves, and thus improve significantly on the existing non-relativistic treatments in the literature. These primordial Weibel magnetic fields may serve as cosmological seed fields for even stronger magnetic fields in cosmological sources. The existence of magnetic fields is a mandatory requirement for the onset of most nonthermal phenomena in cosmological sources especially gamma-ray burst sources and relativistic jet sources. According to current understanding the formation of relativistic jets in centers of galaxies, powered by accretion onto a supermassive black hole, is due to a fast super-Alfvenic MHD wind from the rotating accretion disk where the magnetic field anchored in the accretion disk is crucial for the jet collimation. Relativistic magnetized shock waves form when e.g. a faster wind overtakes the slower wind giving rise to intense acceleration of charged particles by diffusive shock acceleration and subsequent Doppler beamed and superluminal nonthermal radiation components. Studying the nonthermal history of our Universe is closely linked to the understanding of the cosmological magnetization processes.