Interplanetary and Geomagnetic Consequences of Interacting CMEs of 13-14 June 2012

TL;DR

This study analyzes the interaction of two CMEs from June 2012, revealing their inelastic collision and significant geomagnetic effects, including a strong storm and prolonged SSC, highlighting the impact of CME interactions on space weather.

Contribution

It provides detailed kinematic analysis of interacting CMEs and demonstrates their enhanced geoeffectiveness during a specific solar event.

Findings

CME collision was inelastic.

Interaction led to a strong geomagnetic storm.

Prolonged SSC was associated with CME interaction.

Abstract

We report on the kinematics of two interacting CMEs observed on 13 and 14 June 2012. Both CMEs originated from the same active region NOAA 11504. After their launches which were separated by several hours, they were observed to interact at a distance of 100 Rs from the Sun. The interaction led to a moderate geomagnetic storm at the Earth with Dst index of approximately, -86 nT. The kinematics of the two CMEs is estimated using data from the Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) onboard the Solar Terrestrial Relations Observatory (STEREO). Assuming a head-on collision scenario, we find that the collision is inelastic in nature. Further, the signatures of their interaction are examined using the in situ observations obtained by Wind and the Advance Composition Explorer (ACE) spacecraft. It is also found that this interaction event led to the strongest sudden storm commencement (SSC) (approximately 150 nT) of the present Solar Cycle 24. The SSC was of long duration, approximately 20 hours. The role of interacting CMEs in enhancing the geoeffectiveness is examined.