Immanuel Christopher Jebaraj from the solar physics departement presents his research during an online webex-seminar.
Title: Tracking shock waves in the corona and interplanetary space using radio observations and modelling
Abstract:
Shock waves driven by eruptive events such as Coronal mass ejections (CMEs) can provide conditions for particle accelerations and generation of shock-associated radio emission. Type II bursts are radio signatures of fast electron beams accelerated at the shock front, produced when the shock wave propagates through the solar atmosphere.
Ground-based radio observations allow us to study shock waves in the low corona while space-born radio observations provide us opportunity to track shock waves in the inner heliosphere.
The exact location of the type II radio sources on the surface of the shock wave, regions closer to the CME leading edge or the CME-flanks, has been a long-discussed question. We address this question in the study of a shock wave associated with a flare/CME event and complex radio event on September 28, 2011.
We employ a novel approach, combining the results from the radio triangulation analysis with shock wave modelling. In order to model the shock wave, we first reconstructed the shock wave in 3D space using multi-viewpoint EUV and white light observations (from SDO, LASCO, and STEREO spacecraft). Further, we modelled the evolution of shock wave and its parameters using a 3D MHD background coronal model produced by the MAS (Magnetohydrodynamics Around a Sphere Thermodynamic) MHD model.
Our results are based on a two-step analysis. We first analyze the global evolution of the shock parameters and then localize the areas which could be the source regions of radio emission. We analyzed the temporal evolution of the upstream plasma characteristics and the shock wave parameters. Our results reveal the complex relationship between the different shock wave parameters. We believe that the shock wave geometry and its relationship with the shock strength play the most important role in the generation of type II radio emissions.
Webex-link: https://observatory.webex.com/observatory/j.php?MTID=m25274d97deddadb12e6b0a43aa104784
