Iver Cairns, School of Physics, University of Sydney

Title: Type II Solar Radio Bursts: From Fundamental Plasma Physics to Space Weather Research  (Video)

Abstract: For over 60 years type II solar radio bursts have defied detailed quantitative explanation, despite their promise for predicting spaceweather at Earth and their status as the archetype for coherent radio emission stimulated by shocks. Type II bursts are widely accepted to be radio emission produced at the electron plasma frequency and/or twice that frequency upstream from shock waves (usually driven by coronal mass ejections [CMEs]) moving through the corona and solar wind: electrons reflected at the shock develop beam distribution functions, the electron beams drive Langmuir waves, and the Langmuir waves couple linearly and/or nonlinearly to produce the fundamental and harmonic radio emission. At the University of Sydney we have developed quantitative analytic descriptions for the detailed plasma physics of these steps. We have also constructed astate-of-the-art theoretical / simulational model for an arbitrary specified type II burst by combining the above kinetic emission theory with a 3D MHD simulation of the CME and associated shock through a realistic, data-driven, 3D model for the corona and solar wind. Here I demonstrate impressive quantitative agreement between the predicted and observed properties of both coronal and interplanetary type II bursts. These suggest that we are close to "solving the type II problem" and being able to use our simulations of type IIs for space weather prediction.