Insights into Coronal Mass Ejection Shocks with the Irish Low Frequency Array (I-LOFAR)
posterposted on 25.06.2018 by Ciara Maguire, Eoin Carley, Peter Gallagher
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Poster presented at 17th RHESSI workshop held at trinity College Dublin, Ireland (http://rhessi17.lofar.ie).
The Sun can produce large-scale energetic events such as solar flares and coronal mass ejections (CMEs) which can excite shock waves that propagate through the corona. To date, the shock kinematics responsible for particle acceleration and emission at radio wavelengths are not well known. Here, we investigate these phenomena using radio observations of the September 2, 2017 C7.7 solar flare at 10-240 MHz from the recently constructed Irish Low Frequency Array (I-LOFAR; www.lofar.ie<http://www.lofar.ie>). The flare was produced from NOAA Active Region 12672, located on the western limb. SOHO/LASCO recorded a CME that reached maximum speeds of 1041 km/s (average speed of 449 km/s) . Here, we present an analysis of the I-LOFAR observations of a Type II radio burst associated with the shock driven by the CME. In particular, we will describe how features in dynamics spectra obtained using I-LOFAR, such as drift rates and band-splitting, are related to the shock kinematics as derived from imaging observations using the Atmospheric Imaging Assembly (AIA). A combination of I-LOFAR and AIA observations are used to estimate shock velocities, compression ratios and Mach numbers, allowing us to better understand the relationship between the shock kinematics and its radio signature.