SPRG Seminars
November 2, 2010:
" Particle Acceleration at CME-driven shocks near the Sun and in Interplanetary Space "
Dr. Mihir Desai,
SWRI
Coronal Mass Ejection- or CME-driven interplanetary (IP) shocks are responsible for causing both, the so-called large gradual solar energetic particle (SEP) events as well as the energetic storm particle (ESP) events observed at Earth. However, despite recent observational and theoretical advances, many important questions regarding such CME-associated particle events remain unanswered. This is because a number of different physical effects that vary with time and location could contribute and modify the SEP properties by the time they arrive at 1 AU. These effects include: (1) the origin, structure, and obliquity of CME shocks, (2) the nature of wave-particle interactions and the type of turbulence that is present near the shocks, (3) the availability, distribution and composition of the suprathermal seed populations, (4) the type of injection and acceleration processes involved, and (5) the possible distortion of SEP properties (e.g., time- profiles of Fe/O, intensities etc.) during transport to Earth. In this talk, we review key observational features that shed light on the acceleration and transport processes occurring during CME-related SEP and ESP events. Finally, we discuss new measurements of ESP events that can help differentiate between some of the above effects and provide tests for theoretical models that seek to account for the observed properties.