SHINE: Compound Solar Energetic Particle Events in the Heliosphere: Data Analysis and Modeling

Johns Hopkins University, Baltimore MD

Investigators

Abstract

Interplanetary magnetic structures affect solar energetic particle (SEP) transport processes and shape the time-intensity histories of SEP events. Improved understanding of processes leading to major compound SEP events is necessary to determine the most extreme radiation environments in the inner heliosphere. Therefore, the PI will investigate how the state of the interplanetary medium influences the development of major SEP events in the inner heliosphere, how and when the energetic particle 'streaming limit' is violated, and what factors lead to the formation of energetic particle reservoirs. The PI's team will use energetic particle, plasma, and magnetic field data from a number of spacecraft (Cassini, ACE, IMP-8, GOES, Ulysses, Voyagers 1 and 2) to study the largest SEP events of the last three solar cycles. They will investigate the state of the inner heliosphere during these major events, the conditions that preceded SEP intensities exceeding the streaming limit, and the processes that formed energetic particle reservoirs in the inner heliosphere. The PI will model particle transport conditions in compound SEP events using numerical solutions of the transport equation for the evolution of the energetic particle distribution function. This numerical model includes the effects of solar wind convection, pitch-angle scattering, pitch-angle focusing, and adiabatic deceleration under the conditions in which multiple SEP events occur. The results of this research will be broadly disseminated in the form of publications, presentations at annual SHINE meetings, as well as at other workshops and seminars. The majority of research will be carried out by the PI and a summer intern college student. This research will also directly benefit the engineering teams that need to estimate the impact of SEPs on both space instrumentation and human space-flight.