Space Weather | Publications | Presentations | Outreach | Teaching
I have done the part of my doctoral dissertation work on developing and validating a numerical model of propagation and acceleration of highly energetic charged particles that stream into the solar system from the Sun. These particles can be accelerated to very high energies, and may cause disruption of electrical systems on spacecraft and pose serious health risks to astronauts. The characterization of this high energy particle radiation at various locations in the solar system is one of the objectives of the Earth-Moon-Mars Radiation Environment Module (EMMREM) project at the Center for Space Physics at BU. I have worked on this project for the past several years. Here is a paper describing this project.
Interplanetary shocks have been quite well studied, thanks to in situ measurements of energetic particles near Earth and throughout the solar system. Many bursts of energetic charged particles observed close to Earth are not directly associated with shocks that pass by Earth. This suggests that energetic particles are formed much lower, in the solar corona, possibly by shocks that form near the Sun or through magnetic reconnection. The difficulty with forming shocks close to the Sun is that the medium is so strongly mediated by magnetic fields that shock formation becomes difficult. Compression regions may play a critical role in modifying plasma dynamics so severely that shocks form more readily than previously thought. Magnetic reconnection also likely plays a major role in the outflows of reconnection jets.
I analyze remote optical and ultraviolet observations of the low solar corona to characterize how shocks and reconnection regions form close to the Sun and to investigate how they accelerate charged particles. Specifically, I use ultraviolet observations of the Sun from the recently-launched Solar Dynamics Observatory/ Atmospheric Imaging Assembly, in order to constrain the properties of plasma shocks and magnetic reconnection regions in the solar corona, which can accelerate particles. I also apply the numerical particle propagation and particle acceleration model to study the origin and acceleration of solar energetic particles. This work will help address the question of whether plasma shocks and/or magnetic reconnection regions are efficient in accelerating particles close to the Sun. It will also lead to new techniques for characterizing and predicting the interplanetary radiation environment, an important topic in the field of space weather.