Propagation of the 2012 March Coronal Mass Ejections from the Sun to Heliopause

TL;DR

This study models the propagation of 2012 solar coronal mass ejections through the heliosphere, predicting their arrival at the heliopause around 120 AU and correlating with Voyager 1 observations.

Contribution

It provides a detailed MHD simulation of CME propagation from the Sun to the heliopause, linking solar eruptions to outer heliosphere phenomena.

Findings

Shock and MIR reach 120 AU around April 2013

Model predictions align with Voyager 1 cosmic ray data

Heliopause is estimated at approximately 120 AU

Abstract

In 2012 March the Sun exhibited extraordinary activities. In particular, the active region NOAA AR 11429 emitted a series of large coronal mass ejections (CMEs) which were imaged by STEREO as it rotated with the Sun from the east to west. These sustained eruptions are expected to generate a global shell of disturbed material sweeping through the heliosphere. A cluster of shocks and interplanetary CMEs (ICMEs) were observed near the Earth, and are propagated outward from 1 AU using an MHD model. The transient streams interact with each other, which erases memory of the source and results in a large merged interaction region (MIR) with a preceding shock. The MHD model predicts that the shock and MIR would reach 120 AU around 2013 April 22, which agrees well with the period of radio emissions and the time of a transient disturbance in galactic cosmic rays detected by Voyager 1. These results are important for understanding the "fate" of CMEs in the outer heliosphere and provide confidence that the heliopause is located around 120 AU from the Sun.