NSF Award
1923377
Solar eruptions, in the form of flares and coronal mass ejections (CMEs), are violent explosions in the Sun's atmosphere that propel millions of tons of hot plasma into interplanetary space. They are the largest energy-release events in the solar system and the main driver of space weather disturbances at Earth. When directed towards the Earth, they can adversely affect human endeavors such as air traffic communications, power grids, and satellites, and be hazardous to astronauts traveling in space. It is therefore important to understand the physics behind these powerful events. It is widely accepted that the sudden and violent reconfiguration of magnetic fields is the main process that enables the release of energy in solar eruptions. However, the details of the conversion of magnetic energy into heating and plasma motion are not well understood. In this three-year project, state-of-the-art computer simulations together with satellite observations will be employed to make progress on this important problem, by modeling and systematically investigating energy transfer and plasma heating in flares and CMEs. The project will support the dissertation research of a PhD student and thus foster the educational goals of the NSF.<br/><br/>This three-year project will employ sophisticated magnetohydrodynamic (MHD) numerical simulations to model solar eruptions (for both idealized and observed cases). The simulation results will be used to identify the physical mechanisms responsible for energy conversion and plasma heating during eruptions and to quantify their respective contributions. These numerical investigations will be complemented with detailed analysis of high-cadence and high-resolution observations from current spacecraft, using well-developed analysis tools for deriving thermal information from observational data. This project aims to answer several open questions about solar eruptions. First of all, it will examine the physical mechanisms that heat plasma during the impulsive phase of solar flares and quantify the energy partition in this phase. Secondly, it will explore the physical mechanisms responsible for heating plasma in the region of the current sheet in the late phase of solar flares. Thirdly, it will investigate how the recently discovered "hot plasma channels" are formed and heated to temperatures of more than 10 million degrees Kelvin in the early stages of an eruption. Finally, it will examine how erupting plasma is heated and evolves during its propagation within a CME. The research and EPO agenda of this project supports the Strategic Goals of the AGS Division in discovery, learning, diversity, and interdisciplinary research.<br/><br/>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.
