Studying the extended magnetic structure of the April 12, 2014 interplanetary CME using in situ detection of shock fronts

Abstract:

We present a study of the frontal and magnetic structure of the interplanetary CME (ICME) April 12, 2014 using in-situ multi-spacecraft detections provided by the missions: Wind and STEREO. Initially, we inspect the potential interplanetary shock fronts at 1AU induced by an ICME transient in different regions over the leading edge. We performed a review of all interplanetary shocks detected by these missions in two time periods: 2007-2010 and the first five months of 2014, with the aim of finding ICME-driver shock detected in three or two different regions. In that survey, we find one clear event that fulfill the conditions: the ICME of April 12-14, 2014. For that event, we report some shock parameters, the profiles of the main physical features of the proton plasma, the radio emission and the electron beam spectra for both spacecraft of STEREO mission. We assert that the region downstream of the detected interplanetary shock corresponds to a turbulent and intense magnetic field region, where electron flux generate a radio emission that saturates the instrument. We conclude that the two detection, over the two regions of the shock front, probably are associated to different dynamical processes due to the particular interaction that take place there. Moreover, with the aim of studying the magnetic cloud structure associated to the April 12-14, 2014 ICME event, we evaluate a model of magnetic structure derived from force-free plasma configuration over a spherical symmetry knows as Spheromak structure in order to compare it with the real data. We produce artificial magnetic field profiles (magnetic field strength and its three components in RTN coordinate system) which was compared with the magnetic cloud detected. The results suggest a correlation between the model and STEREO-B, which detect the bulk structure. We conclude that the magnetic structure of this magnetic cloud has toroidal topology similar to a closed flux rope structure.