Particle Acceleration During Collisionless Magnetic Reconnection

这一研究项目将侧重于磁化天体物理等离子体中粒子加速的起源。太阳和其他恒星，许多行星系统和其他天体都产生磁场。观测表明，当指向相反方向的磁场在这些系统中聚集在一起时，它们可以相互湮灭并爆炸性地释放磁能。这些爆炸表现在太阳和恒星耀斑、天体物理物体的耀斑、地球空间环境的风暴以及实验室聚变实验的中断。磁能释放也是空间天气的驱动因素，这可能对卫星通信产生负面影响，并威胁到太空中的宇航员。 磁场重联是描述磁场湮灭的基本过程。在理解自然界和实验室中看到的快速释放磁能的机制方面取得了很大进展。粒子加速的机制还没有得到很好的理解，这是这项研究资助的重点。 本科生的积极参与和研究生，包括女研究生的培训，进一步扩大了NSF的广泛的教育目标。该研究计划的目标是了解磁重联过程中的电子和离子加热和加速，并开发一个粒子加速模型，可以与观测进行比较。粒子在细胞中的模拟加上分析的努力将被用来解决两个关键问题有关的电子和离子加速在磁重联：（1）离子加速的机制与脉冲耀斑的丰度增强的应用，和（2）的物理基础无处不在的高能电子和离子的幂律谱的观测。将实施一种新的计算模型来探索宏观尺度系统中的粒子加速，该模型可用于预测天体物理等离子体中高能粒子的光谱、光子和无线电特征。该奖项反映了NSF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 research project will focus on the origins of particle acceleration in magnetized astrophysical plasmas. The sun and other stars, many planetary systems and other astronomical objects produce magnetic fields. Observations reveal that when magnetic fields pointing in opposite directions come together in these systems, they can annihilate each other and explosively release magnetic energy. These explosions are revealed in solar and stellar flares, flares in astrophysical objects, storms in Earth's space environment and disruptions in laboratory fusion experiments. Magnetic energy release is also the driver of space weather, which can negatively impact satellite communications and threaten astronauts in space. Magnetic reconnection is the fundamental process that describes how magnetic fields annihilate. Great progress has been made on understanding the mechanisms for the fast release of magnetic energy seen in nature and the laboratory. The mechanisms for particle acceleration are not well understood and are the focus of this research grant. The active involvement of undergraduate students and the training of graduate students, including female graduate students, furthers the broad educational goals of NSF.The goal of this research program is to understand electron and ion heating and acceleration during magnetic reconnection and to develop a model for particle acceleration that can be compared with observations. Particle-in-cell simulations coupled with an analytic effort will be used to address two key issues related to electron and ion acceleration during magnetic reconnection: (1) the mechanism for ion acceleration with application to abundance enhancements in impulsive flares, and (2) the physics basis for the ubiquitous observations of powerlaw spectra of energetic electrons and ions. A novel computational model will be implemented to explore particle acceleration in macro-scale systems that can be used to predict the spectra and photon and radio signatures of energetic particles in astrophysical plasmas. Collaborations will be continued and expanded with scientists working on laboratory experiments, satellite data and ground-based data to benchmark the theoretical predictions with observations.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.