CME -- HSS interaction and characteristics tracked from Sun to Earth

TL;DR

This study investigates the early evolution and interaction of a CME with a high-speed solar wind stream from a coronal hole, analyzing its deflection and impact on Earth using multi-viewpoint data and modeling.

Contribution

It provides a detailed analysis of CME-HSS interaction from the Sun to Earth, including deflection and magnetic configuration changes, using combined observational and modeling approaches.

Findings

CME experienced a north-eastward deflection of at least 30 degrees.

Interaction between CME and HSS starts at 1.3 to 3 solar radii.

The study enhances understanding of CME propagation and Earth impact mechanisms.

Abstract

In a thorough study, we investigate the origin of a remarkable plasma and magnetic field configuration observed in situ on June 22, 2011 near L1, which appears to be a magnetic ejecta (ME) and a shock signature engulfed by a solar wind high-speed stream (HSS). We identify the signatures as an Earth-directed coronal mass ejection (CME), associated with a C7.7 flare on June 21, 2011, and its interaction with a HSS, which emanates from a coronal hole (CH) close to the launch site of the CME. The results indicate that the major interaction between the CME and the HSS starts at a height of 1.3 Rsun up to 3 Rsun. Over that distance range, the CME undergoes a strong north-eastward deflection of at least 30 degrees due to the open magnetic field configuration of the CH. We perform a comprehensive analysis for the CME-HSS event using multi-viewpoint data (from the Solar TErrestrial RElations Observatories, the Solar and Heliospheric Observatory and the Solar Dynamics Observatory), and combined modeling efforts (nonlinear force-free field modeling, Graduated Cylindrical Shell CME modeling, and the Forecasting a CMEs Altered Trajectory ForeCAT model). We aim at better understanding its early evolution and interaction process as well as its interplanetary propagation and related in situ signatures, and finally the resulting impact on the Earth's magnetosphere.