000004553 001__ 4553
000004553 005__ 20200115160047.0
000004553 037__ $$aPOSTER-2020-0012
000004553 100__ $$aJebaraj, Immanuel
000004553 245__ $$aA new approach to interpret interplanetary radio observations for forecasting shock arrival at Earth
000004553 260__ $$c2019
000004553 269__ $$c2019-11-18
000004553 520__ $$aA shock wave is an energetic compressible pressure wave propagating faster than the speed of the medium which accelerates particles in the low corona and interplanetary space and are well observed by in-situ spacecraft. Tracking of shock waves and predicting their arrival at the Earth is therefore an important scientific goal. Space based radio observations provide us the unique opportunity to track shock waves in the inner heliosphere.   We present a novel technique which transcends the existing 2D analysis of radio emissions in interplanetary space using 1D density models. Using stereoscopic radio observations from the WAVES instrument onboard WIND, STEREO A and STEREO B, we identify the source positions of interplanetary radio emissions, namely, type III bursts (signatures of fast electron beams propagating along open field lines) and type II bursts (signature of shock waves).  We present the extensive study of the CME/flare event on September 27/28, 2012. The GOES C3.7 flare that originated from NOAA AR 1577 was associated with a full-halo CME (first seen in the SOHO/LASCO C2 field of view at 23:47 UT) and white light shock wave observed by all three spacecraft STEREO A, STEREO B, and SOHO. The associated radio event is composed of a groups of type III bursts and two type II bursts with different starting time and starting frequencies. In this event, we were able to clearly separate groups of type III bursts associated with impulsive and decay phase of the flare. We found the origin of the type II bursts to be significantly more complex than in the case of the type III bursts. While the first type II burst shows clear association with the acceleration phase of the CME, the second type II is of unclear origin. To understand the association of the radio emission and the CME/flare event, we perform multi-wavelength and radio triangulation study using goniopolarimetric observations by STEREO/WAVES and WIND/WAVES. We also model propagation of the CME using the data-driven EUHFORIA cone model (EUropean Heliospheric FORecasting Information Asset) and compared results with in-situ observations. Results of the study show completely different type III source positions for groups of bursts associated with impulsive and decay phase of the flare. We also found that while the first type II is clearly CME-driven, the second type II burst (with a low starting frequency) occurs significantly higher in the solar corona than the CME, and has unclear origin.  Since the radio source positions of the second type II coincide with the group of the decay phase type III bursts, and are situated close to the nearby streamer, we believe that both type of bursts are generated during the interaction between the shock wave and the streamer. We also demonstrate the importance of radio triangulation studies in understanding the relationship between the CME/flare events, their associated radio emissions and the propagation of shock wave interplanetary space. 
000004553 594__ $$aNO
000004553 700__ $$aMagdalenic, Jasmina
000004553 700__ $$aScolini, Camilla
000004553 700__ $$aPodlachikova, Tatiana
000004553 700__ $$aDissauer, Karin
000004553 700__ $$aPomoell, Jens
000004553 700__ $$aRodriguez, Luciano
000004553 700__ $$aKilpua, Emilia
000004553 700__ $$aKrupar, Vratislav
000004553 700__ $$aVeronig, Astrid
000004553 700__ $$aPoedts, Stefaan
000004553 773__ $$tESWW 16, Liege
000004553 8560_ $$fimmanuel.jebaraj@observatoire.be
000004553 980__ $$aCPOSTER