Cosmic Ray-Modified Astrophysical Shocks: Modeling and Observations

目前在宇宙线(CR)研究中占主导地位的范式认为，能量低于Peta电子伏特的银河系CRS的大部分是通过扩散激波加速在超新星遗迹(SNR)中产生的。这现在正处于一个转折点：很快，从射电波段到伽马射线再到高能中微子，理论计算和观测之间的比较有望要么证实这一范式，要么呼吁范式转变。该项目将开发新的理论和观测技术来测试SNR范式。理论研究基于一个共同的主题：宇宙射线如何改变激波的结构？这项工作将研究CRS的磁场放大、注入和加速，以及尘埃溅射和上游等离子体中的大中性成分的作用。分析所谓的巴尔默主导激波中的中性氢应该会导致一种测量激波加速效率的新方法。这项研究将包括考虑宇宙射线如何逃离其加速点并向地球传播，以及CRS的动力学扩散。与时间和空间相关的粒子动力学模型将与观测到的非热丝进行比较，并与高能粒子观测的结果相联系。这是一个涉及天体物理和等离子体物理的数据分析以及理论和计算工作的多学科项目。与普渡大学计算机图形技术系的学生合作，将与普渡大学发现学习中心合作建立一个互动信息亭，向包括K-12学生、教师和普通公众在内的所有参观团体解释关于CRS的情况。

The current dominant paradigm in cosmic ray (CR) research says that the bulk of Galactic CRs with energies below a peta-electron volt are created in supernova remnants (SNRs) via diffusive shock acceleration. This is now at a turning point: soon, the comparison between theoretical calculations and observations from the radio band to gamma rays to high energy neutrinos is expected to either confirm the paradigm or call for a paradigm shift. This project will develop novel theoretical and observational techniques to test the SNR paradigm. The theoretical studies are based around a common theme: how do cosmic rays modify the structure of the shock? The work will investigate magnetic field amplification, injection and acceleration of CRs, and the role of dust sputtering and the large neutral component in the upstream plasma. Analysis of neutral hydrogen in the so-called Balmer-dominated shocks should lead to a novel way to measure the shock acceleration efficiency. The research will include consideration of how cosmic rays escape their acceleration sites and propagate towards the Earth and of the kinetic diffusion of CRs. Modeling of time- and spatially-dependent particle dynamics will be compared with observed non-thermal filaments and tied to the results of high energy particle observations.This is a multidisciplinary project involving data analysis and theoretical and computational work in astrophysics and plasma physics. Work with students in the Purdue Computer Graphics Technology Department will lead to an interactive kiosk, in partnership with Purdue's Discovery Learning Center, to explain about CRs to all visiting groups, including K-12 students, teachers, and the general public.