Transport processes of high-energy cosmic rays in the interstellar medium

高能宇宙线在星际介质中的传输过程

• 批准号: 263050076
• 负责人: Professor Dr. Dieter Breitschwerdt
• 金额: --
• 依托单位: Zentrum für Astronomie und Astrophysik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/263050076?language=en
• 关键词: Transport; processes; energy; cosmic; rays

Cosmic rays (CRs) are energetic particles that arrive on Earth in a continuous stream. The main component (90%) is represented by protons, with the rest being alpha particles (<= 10%), electrons, and heavier nuclei. The acceleration mechanisms of the CR particles with the highest energies known is still largely unknown, partly because the sources have not yet been identified. Correlations with AGNs in the local universe are still uncertain, also because of the low number density of such high-energy particles.It is the aim of this project to investigate the scattering of highest-energy CR particles in the turbulent electromagnetic fields of the interstellar medium (ISM). We will evaluate the transport processes of particles with various masses, ranging from electrons to iron nuclei. This will address the problem of a possible deflection and isotropization of extra-galactic CRs and the energy threshold (i.e., the Hillas limit) up to which this is possible.For this purpose numerical magneto-hydrodynamical (MHD) simulations of the ISM will be performed. They will provide insight into the evolution of MHD turbulence driven by supernova-induced shock waves. The transport of CRs will be investigated using two different approaches: (i) test-particles will be injected into the simulation cube and their trajectories are traced during the evolution of the magnetized medium; (ii) based on magnetic field correlation parameters from the MHD simulation Monte-Carlo simulations with a test-particle code will be carried out.The combination of independent methods will allow for a critical judgment of the assumptions used in the investigations and will therefore increase the reliability of the obtained transport parameters. Answering the questions of the origin of high-energy CRs will not only allow for an increased understanding of the nature of the most energetic particles known, but will also help the understanding of magnetic turbulence in general.

宇宙射线（CRS）是在连续的溪流中到达地球的能量颗粒。主要成分（90％）由质子表示，其余的是α颗粒（<= 10％），电子和较重的核。已知能量最高的Cr颗粒的加速机制仍然很大程度上是未知的，部分原因是尚未确定来源。与本地宇宙中AGN的相关性仍然不确定，这也是因为这种高能颗粒的数量密度较低。该项目的目的是研究星际介质的湍流电磁场中最高能量CR颗粒的散射（ISM）。我们将评估各种质量的颗粒的传输过程，从电子到铁核。这将解决可能会导致可能的偏转和各向同性的问题（即Hillas liber），这是可能的。为此，将执行ISM的数值磁通磁力 - 氢动力学（MHD）模拟。他们将洞悉由超新星引起的冲击波驱动的MHD湍流的演变。将使用两种不同的方法研究CRS的运输：（i）将测试粒子注入模拟立方体，并在磁化培养基的演变过程中追溯其轨迹； （ii）将基于MHD模拟蒙特卡洛模拟的磁场相关参数，并进行测试粒子代码。独立方法的组合将允许对研究中使用的假设进行批判性判断，因此将提高所获得的运输参数的可靠性。回答高能量CRS的起源问题不仅可以增加对已知颗粒最有能力的颗粒本质的理解，而且还将有助于一般来说了解磁性湍流。