Research Article

Heliospheric tracking of enhanced density structures of the 6 October 2010 CME

¹ Udaipur Solar Observatory, Physical Research Laboratory, Udaipur 313001, India
² Center of Excellence in Space Sciences India (CESSI), IISER Kolkata, Mohanpur 741246, India

^* Corresponding author: wageesh@prl.res.in

Received: 21 November 2014
Accepted: 13 June 2015

Abstract

A Coronal Mass Ejection (CME) is an inhomogeneous structure consisting of different features which evolve differently with the propagation of the CME. Simultaneous heliospheric tracking of different observed features of a CME can improve our understanding about relative forces acting on them. It also helps to estimate accurately their arrival times at the Earth and identify them in in-situ data. This also enables finding any association between remotely observed features and in-situ observations near the Earth. In this paper, we attempt to continuously track two density enhanced features in the CME of 6 October 2010, one at the front and another at the rear edge. This is achieved by using time-elongation maps constructed from STEREO/SECCHI observations. We derive the kinematics of the tracked features using various reconstruction methods. The estimated kinematics are used as inputs in the Drag Based Model (DBM) to estimate the arrival time of the tracked features of the CME at L1. On comparing the estimated kinematics as well as the arrival times of the remotely observed features with in-situ observations by Advanced Composition Explorer (ACE) and Wind, we find that the tracked bright feature at the rear edge of 6 October 2010 CME corresponds most probably to the enhanced density structure after the magnetic cloud detected by ACE and Wind. In-situ plasma and compositional parameters provide evidence that the rear edge density structure may correspond to a filament associated with the CME while the density enhancement at the front corresponds to the leading edge of the CME. Based on this single event study, we discuss the relevance and significance of Heliospheric Imager (HI) observations in identification of the three-part structure of the CME.