Abstract Details
| Name: Surajit Mondal Affiliation: NCRA-TIFR, Pune Conference ID: ASI2019_510 Title : Measuring the magnetic field of CMEs using spectroscopic snapshot imaging with the MWA Authors and Co-Authors : Surajit Mondal, Divya Oberoi, Kamen Kozarev, Atul Mohan Abstract Type : Poster Abstract Category : Sun and the Solar System Abstract : Most studies on Coronal Mass Ejections (CMEs) using radio data were done with the dynamic spectrum and mainly concentrated on the intense type II plasma emission arising due to electron acceleration at the shock fronts. This limits their utility for studying the CME plasma itself and the regions of CME away from the shock front. Gyrosynchrotron emission from the electrons accelerated during the CME initiation process trapped in the magnetised CME plasma has long been expected, but has remained hard to observe. This emission was first detected by Bastian et al. (2001). Using the spatially resolved spectra of the detected CME radio loop, they quantified the CME magnetic field as well as the non-thermal electron population responsible for this emission. Not only are these parameters inaccessible by any other means, they also play a very important role from a space weather perspective. Here we present the detection of a white light CME using radio data from the Murchison Widefield Array (MWA). Imaging was done at nine spectral bands, each 2 MHz wide, spanning 108 MHz to 240 MHz. Unlike earlier studies, we find a clear structural correspondence between the observed radio structure and the white light CME. We are also able to detect the flux rope for a longer duration and out to a larger distance, as compared to earlier studies. By modelling the spectra, we are able to constrain the magnetic field and energy distribution of the nonthermal electrons in a spatially resolved manner. Finally, we present a comprehensive comparative analysis of all the earlier studies where similar measurements were made. We comment on why, we believe, that the MWA with its high imaging dynamic range and wide bandwidth can make a significant impact in advancing our understanding of CMEs. |