Combined Treatment of Particle Acceleration in Solar Flares and Associated CME Shocks
Speaker :Vahe’ Petrosian
Vahe Petrosian, Professor of physics and applied physics, Chairman of Astronomy Program, Department of Physics, Stanford University.
Awards and recognition: 1972-74 Alfred P. Sloan Fellow; Member, Eta Kappa Nu, Tau Beta Pi; Center for Space Science and Astrophysics & KIPAC, Stanford University; Co-discoverer of strong gravitational lensing of cluster of galaxies, Inventor of Petrosian criteria (magnitude, ratio) with non-parametric methods for determination of distribution of astronomical sources from truncated data.
Abstract : Solar eruptive events produce flares in the corona and coronal mass ejections (CMEs). Particles are accelerated both in the coronal reconnection sites and in the CME driven shocks. Traditionally, investigations of these phenomena are carried out independently in two communities. The solar community's focus is on flares and radiation producing particles (RPPs), while the heliospheric community's focus is solar energetic particles (SEPs) and the acceleration in the CME-shocks. However, there is considerable observations, in particular in impulsive-prompt events, indicating a close connection between these two processes. This connection will be the focus of this talk. I will review some relevant observations and describe their modeling based on a hybrid stochastic acceleration at the flare site, and re-acceleration of flare particles injected into the CME environment. Such a model seem to be required to explain Fermi observations of up to several GeV gamma-rays from three behind the limb flares. I will emphasize an important aspect that plays a central role in this scenario, which is the processes of transport and escape of accelerated particles up and down from flare site and from downstream and upstream of the CME-shock.
