Collaborative Research: Turbulence, Structures, and Diffusive Shock Acceleration

这个项目将进一步加深我们对高能粒子的起源和性质的理解，这些粒子在外层空间的冲击波中被加速。众所周知，行星际和星际介质中的激波可以将带电粒子加速到非常高的（相对论性）能量。具体如何做到这一点仍然是一个重要的悬而未决的问题。高能粒子照射地球、绕地球运行的卫星和宇航员，以及探测日球层和其他行星的航天器。高能粒子对生物系统和技术系统构成危害，包括通信、定位、观测和研究卫星。因此，确定高能带电粒子的起源和后续特性可能会对我们的日常生活甚至美国的国家安全产生重要的技术和生物学影响。该奖项将支持阿拉巴马大学亨茨维尔分校和新墨西哥财团在能源部的支持下开展的一项合作，研究复杂等离子体结构对行星际空间高能粒子产生的影响，这些结构通常是在冲击波中产生的。该项目将首次开发激波产生的湍流中粒子能量的定量和可测试模型，这些模型依次通过重连电流层、相关磁等离子体和粒子能量来消散。快速激波湍流尾迹中扩散激波加速度（DSA）和粒子加速度的耦合自然地分裂为两个部分：A)无碰撞激波中湍流和结构的产生、传输和放大，B)电子和离子在无碰撞激波湍流尾迹处和尾迹中的耦合加速度。该项目将1)开发模型，通过模拟验证，描述通过无碰撞的准垂直和准平行激波的湍流传输和产生；2)确定无碰撞冲击是否能在冲击下游产生磁性结构，并将通过重连相关过程描述冲击产生的结构的下游演化；3)解释磁结构和电流片（包括日球层电流片）与入射激波的相互作用；4)利用湍流、磁性结构和与激波相互作用的电流片的数值模型和观测，发展激波附近粒子加速的理论。

This project will further our understanding of the origin and properties of highly energetic particles accelerated at shock waves in outer space. Shock waves in the interplanetary and interstellar medium are known to accelerate charged particles to very high (relativistic) energies. Exactly how this is done remains an important open problem. Energized particles irradiate the Earth, satellites and astronauts orbiting the Earth, and spacecraft exploring the heliosphere and other planets. Highly energetic particles represent a hazard to biological systems and technological systems, including communication, positioning, and observational and research satellites. Thus, determining the origin and subsequent properties of very energetic charged particles can have important technological and biological consequences that impact our daily lives and even the national security of the US. This award will support a collaborative effort between the University of Alabama - Huntsville and the New Mexico Consortium, with support from the Department of Energy, to investigate the effects of complex plasma structures that are typically generated at shock waves on the production of highly energetic particles in interplanetary space. This project will, for the first time, develop quantitative and testable models of particle energization in shock generated turbulence, which is in turn dissipated via reconnection current layers, associated magnetic plasmoids, and particle energization. The coupling of diffusive shock acceleration (DSA) and particle acceleration in the turbulent wake of fast shocks cleaves naturally into two: A) the generation, transmission, and amplification of turbulence and structures at collisionless shock waves, and B) the coupled acceleration of electrons and ions at and in the turbulent wake of collisionless shocks. This project will 1) develop models, validated by simulations that describe the transmission and generation of turbulence through and at collisionless quasi-perpendicular and quasi-parallel shock waves; 2) determine whether collisionless shocks can generate magnetic structures downstream of the shock and will describe the downstream evolution of shock-generated structures through reconnection-related processes; 3) explain the interaction of magnetic structures and current sheets, including the heliospheric current sheet, with incident shock waves; and 4) use numerical models and observations of turbulence, magnetic structures, and current sheets interacting with shocks to develop a theory of particle acceleration in the vicinity of shock waves.