Cosmological magnetic field generation by the Weibel instability

韦贝尔不稳定性产生的宇宙磁场

• 批准号: 13800257
• 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: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2008-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/13800257?language=en
• 关键词: Cosmological; magnetic; field; generation; Weibel

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.

导致星系际介质磁化的过程尚不清楚。宇宙中的大尺度结构，如星系的细丝和薄片，是由最初过密区域的引力坍缩演化而来的，这引起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。建议调查的条件下，在星系际介质中的磁场可能会产生由于韦伯型不稳定性，涉及互穿电子流。由于星系际介质的高温，韦伯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，从而显着改善现有的非相对论性处理在文献中。这些原始的韦伯磁场可能是宇宙学源中更强磁场的宇宙学种子场。磁场的存在是宇宙学源，特别是伽玛射线暴源和相对论喷流源中大多数非热现象发生的必然要求。根据目前的理解，星系中心的相对论喷流的形成，由超大质量黑洞的吸积提供动力，是由于来自旋转吸积盘的快速超阿尔夫文MHD风，其中吸积盘中锚定的磁场对喷流准直至关重要。相对论磁化冲击波的形成，例如当一个较快的风超过较慢的风，引起强烈的加速带电粒子的扩散冲击加速和随后的多普勒波束和超光速非热辐射组件。研究我们宇宙的非热历史与理解宇宙磁化过程密切相关。