The Relation between EIT Waves and Coronal Mass Ejections

TL;DR

This study investigates the spatial relationship between EIT waves and CMEs, finding that EIT wave fronts are co-spatial with CME leading loops and suggesting a common magnetic origin for both phenomena.

Contribution

It provides observational evidence linking EIT waves to CME structures and proposes a new interpretation of CME leading loops as density enhancements caused by magnetic loop stretching.

Findings

EIT wave fronts are co-spatial with CME leading loops.

EIT waves/dimmings are the EUV counterparts of CME structures.

CME stopping near coronal hole boundary is a common feature.

Abstract

More and more evidence indicates that "EIT waves" are strongly related to coronal mass ejections (CMEs). However, it is still not clear how the two phenomena are related to each other. We investigate a CME event on 1997 September 9, which was well observed by both EUV imaging telescope (EIT) and the high-cadence MK3 coronagraph at Mauna Loa Solar Observatory, and compare the spatial relation between the "EIT wave" fronts and the CME leading loops. It is found that "EIT wave" fronts are co-spatial with the CME leading loops, and the expanding EUV dimmings are co-spatial with the CME cavity. It is also found that the CME stopped near the boundary of a coronal hole, a feature common to observations of "EIT waves". It is suggested that "EIT waves"/dimmings are the EUV counterparts of the CME leading loop/cavity, based on which we propose that, as in the case of "EIT waves", CME leading loops are apparently-moving density enhancements that are generated by successive stretching (or opening-up) of magnetic loops.