Particle Acceleration During Collisionless Magnetic Reconnection

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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.