CME Propagation Characteristics from Radio Observations

TL;DR

This paper investigates the propagation of coronal mass ejections (CMEs) and associated shock waves from the Sun to Earth using radio, white-light, and scintillation data, highlighting challenges in velocity estimation during CME travel.

Contribution

It compares multiple density models and observational methods to analyze CME shock speeds and propagation, providing insights into their interplanetary travel characteristics.

Findings

Radio-derived shock speeds vary with density models.

White-light cone model velocities are consistent with radio estimates.

Propagation time estimates are affected by observational uncertainties.

Abstract

We explore the relationship among three coronal mass ejections (CMEs), observed on 28 October 2003, 7 November 2004, and 20 January 2005, the type II burst-associated shock waves in the corona and solar wind, as well as the arrival of their related shock waves and magnetic clouds at 1 AU. Using six different coronal/interplanetary density models, we calculate the speeds of shocks from the frequency drifts observed in metric and decametric radio wave data. We compare these speeds with the velocity of the CMEs as observed in the plane-of-the-sky white-light observations and calculated with a cone model for the 7 November 2004 event. We then follow the propagation of the ejecta using Interplanetary Scintillation (IPS) measurements, which were available for the 7 November 2004 and 20 January 2005 events. Finally, we calculate the travel time of the interplanetary (IP) shocks between the Sun and Earth and discuss the velocities obtained from the different data. This study highlights the difficulties in making velocity estimates that cover the full CME propagation time.