Particle Acceleration During Collisionless Magnetic Reconnection

这个研究项目将集中研究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会产生磁场。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释放磁能。这些爆炸在太阳和恒星的耀斑、天体物理物体的耀斑、地球空间环境中的风暴和实验室聚变实验的中断中被揭示出来。磁能释放也是空间天气的驱动因素，它会对卫星通信产生负面影响，并威胁到太空中的宇航员。磁重联是描述磁场如何湮灭的基本过程。在理解自然界和实验室中看到的磁能快速释放的机制方面取得了很大进展。粒子加速的机制还没有被很好地理解，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）的培养，进一步促进了国家科学基金会广泛的教育目标。这项研究计划的目标是了解磁重联过程中电子和离子的加热和加速，并开发一个可以与观测相比较的粒子加速模型。细胞内粒子模拟结合分析工作将用于解决磁重联过程中与电子和离子加速相关的两个关键问题：(1)离子加速机制与脉冲耀斑丰度增强的应用；(2)高能电子和离子幂律谱普遍观测的物理基础。一个新的计算模型将用于探索宏观尺度系统中的粒子加速，该系统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。将继续并扩大与从事实验室实验、卫星数据和地面数据工作的科学家的合作，以观测作为理论预测的基准。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 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.