A Kinetic Investigation of Plasma Instabilities Driven By Energetic Particles

这个项目将使人们更好地了解宇宙中宇宙射线的产生。宇宙中充满了等离子体，这是一种电离气体，磁场和带电粒子在相互作用下演化。一小部分带电粒子可能会被加速到非常大的能量，尽管它们的数量不到百分之一，但会以一种显著的方式影响整个等离子体。该项目旨在通过可控的、自一致的等离子体数值模拟来研究高能粒子在太阳系和其他天体物理环境中产生和受到磁场影响的过程。该项目将培训研究生和本科生，特别强调吸引代表性不足的少数民族进入该领域，而新知识可能会提高我们预测太空天气的能力，并可能影响未来聚变反应堆的设计。非热粒子可以通过几种不同的物理现象产生，如冲击、磁重联和湍流，利用系统的自由能，无论是动能还是磁性。太阳高能粒子在日球层的流动和天体物理背景下的宇宙射线自然地在热等离子体中产生恢复反反应，这导致初始磁场的缠结/放大。动力学粒子在电池中的模拟将被用来量化从头开始的高能粒子的自生散射，以及能量如何分配到电磁场、等离子体加热和体运动中。高能离子和电子驱动的不稳定性是各种空间/天体物理环境（如无碰撞冲击、太阳风和脉冲星风星云）的现象学的关键。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project will enable better understanding of the generation of cosmic rays throughout the Universe. The Universe is permeated with plasma, an ionized gas where magnetic fields and charged particles evolve under their mutual interaction. A small fraction of the charged particles may be accelerated to very large energies and, despite being less than one percent in number, affect the overall plasma in a prominent way. The project aims to study via controlled, self-consistent numerical plasma simulations the processes through which such energetic particles generate and are impacted by magnetic fields in the solar system and other astrophysical environments. The project will train graduate and undergraduate students, with particular emphasis on attracting underrepresented minorities into the field, while the new knowledge is likely to improve our ability to predict space weather and may impact design of future fusion reactors.Non-thermal particles can be produced via several different physical phenomena such as shocks, magnetic reconnection, and turbulence, tapping into the free energy of the system, be it kinetic or magnetic. The streaming of solar energetic particles in the heliosphere and cosmic rays in astrophysical contexts naturally produces a restoring back-reaction in the thermal plasma, which leads to tangling/amplification of the initial magnetic field. Kinetic particle-in-cell simulations will be used to quantify ab-initio the self-generated scattering of the energetic particles and how energy is partitioned into electromagnetic fields, plasma heating, and bulk motions. Instabilities driven by energetic ions and electrons are key to the phenomenology of diverse space/astrophysical environments, such as collisionless shocks, the solar wind, and pulsar wind nebulae.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.