Collaborative Research: Turbulence, Structures, and Diffusive Shock Acceleration

该项目将进一步加深我们对在外层空间冲击波中加速的高能粒子的起源和性质的了解。 已知行星际和星际介质中的激波会将带电粒子加速到非常高的（相对论）能量。究竟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，卫星和宇航员绕地球轨道运行，航天器探索日光层和其他行星。高能粒子对生物系统和技术系统，包括通信、定位、观测和研究卫星构成危害。因此，确定高能带电粒子的起源和随后的性质可能会产生重要的技术和生物后果，影响我们的日常生活，甚至美国的国家安全。 该奖项将支持亚拉巴马大学亨茨维尔分校和新墨西哥州财团之间的合作努力，并得到能源部的支持，以调查通常在冲击波中产生的复杂等离子体结构对行星际空间高能粒子产生的影响。该项目将首次开发冲击产生的湍流中的颗粒扩散的定量和可测试模型，这些模型又通过重连电流层、相关的磁性等离子体团和颗粒扩散来消散。快速激波湍流尾流中扩散激波加速（DSA）和粒子加速的耦合自然地分为两部分：A）无碰撞激波中湍流和结构的产生、传输和放大; B）无碰撞激波湍流尾流中电子和离子的耦合加速。该项目将：1）开发模型，并通过模拟加以验证，这些模型描述湍流通过无碰撞准垂直和准平行激波的传播和产生; 2）确定无碰撞激波是否能够在激波下游产生磁性结构，并将描述激波产生的结构通过与重连有关的过程在下游的演变; 3）解释磁结构和电流片（包括日光层电流片）与入射冲击波的相互作用; 4）利用湍流、磁结构和电流片与冲击波相互作用的数值模型和观测结果，发展冲击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.