期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 512, 期 1, 页码 233-244出版社
OXFORD UNIV PRESS
DOI: 10.1093/mnras/stac466
关键词
astroparticle physics; instabilities; ISM: magnetic fields; turbulence; cosmic rays; ISM: supernova remnants
资金
- Extreme Science and Engineering Discovery Environment Texas Advanced Computing Center [TG-AST180008]
- NASA [NNX17AG30G, 80NSSC18K1218, 80NSSC18K1726]
- National Science Foundation (NSF) [AST-1714658, AST1909778, PHY-2010240]
- NSF [AGS1936393]
- Agenzia Spaziale Italiana/Istituto Nazionale di Astrofisica [2017-14-H.O]
The study investigates the formation of cosmic ray bubbles around sources and their diffusion properties and morphology, through simulations.
Cosmic rays (CRs) are thought to escape their sources streaming along the local magnetic field lines. We show that this phenomenon generally leads to the excitation of both resonant and non-resonant streaming instabilities. The self-generated magnetic fluctuations induce particle diffusion in extended regions around the source, so that CRs build up a large pressure gradient. By means of two-dimensional (2D) and three-dimensional (3D) hybrid particle-in-cell simulations, we show that such a pressure gradient excavates a cavity around the source and leads to the formation of a cosmic ray dominated bubble, inside which diffusivity is strongly suppressed. Based on the trends extracted from self-consistent simulations, we estimate that, in the absence of severe damping of the self-generated magnetic fields, the bubble should keep expanding until pressure balance with the surrounding medium is reached, corresponding to a radius of similar to 10-50 pc. The implications of the formation of these regions of low diffusivity for sources of Galactic CRs are discussed. Special care is devoted to estimating the self-generated diffusion coefficient and the grammage that CRs might accumulate in the bubbles before moving into the interstellar medium. Based on the results of 3D simulations, general considerations on the morphology of the.-ray and synchrotron emission from these extended regions also are outlined.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据