Is the enhancement of type II radio bursts during CME interactions related to the associated solar energetic particle event?

Abstract

We investigated 64 pairs of interacting-CME events identified by the simultaneous observations of SOHO and STEREO spacecraft from 2010 January to 2014 August, to examine the relationship between the large SEP events in the energy of 25-60MeV and the properties of the interacting CMEs. We found that during CME interactions the large SEP events in this study were all generated by CMEs with the presence of enhanced type II radio bursts, which also have wider longitudinal distributions comparing to events with the absence of type II radio burst or its enhancement (almost associated with small SEP events). It seems that the signature of type II radio bursts enhancement is a good discriminator between large SEP and small or none SEP event producers during CME interactions. The type II radio burst enhancement is more likely to be generated by CME interactions, with the main CME having larger speed (v), angular width (WD), mass (m) and kinetic energy (E_k), that taking over the preceding CMEs which also have higher v, WD, m and E_k, than those preceding CMEs in CME pairs missing the type II radio bursts or enhancements. Our analysis also revealed that the intensities of associated SEP events correlate negatively with the intersection height of the two CMEs. Most of type-II-enhanced events and SEP events are coincidentally and almost always made by the fast and wide main CMEs that sweeping fully over a relatively slower and narrower preceding CMEs. We suggest that a fast CME with enough energy completely overtaking a relatively narrower preceding CME, especially in low height, can drive more energetic shock signified by the enhanced type II radio bursts. The shock may accelerate ambient particles and lead to large SEP event more easily.

References in corpus (12)

• Observations of an extreme storm in interplanetary space caused by successive coronal mass ejections
• The Interaction of Successive Coronal Mass Ejections: A Review
• Super-elastic Collision of Large-scale Magnetized Plasmoids in The Heliosphere
• Asymmetry in the CME-CME interaction process for the events from 2011 February 14-15
• Full halo coronal mass ejections: Do we need to correct the projection effect in terms of velocity?
• The acceleration characteristics of solar energetic particles in the 2000 July 14 event
• Strength of Coronal Mass Ejection-Driven Shocks Near the Sun, and Its Importance in Predicting Solar Energetic Particle Events
• Flare magnetic reconnection and relativistic particles in the 2003 October 28 event
• Seed population in large Solar Energetic Particle events and the twin-CME scenario
• On the identification of time interval threshold in the twin-CME scenario
• Investigation of the possible source for solar energetic particle event of 2017 September 10
• Model of energy spectrum parameters of ground level enhancement events in solar cycle 23

Cited by in corpus (1)

• Successive Coronal Mass Ejections Associated with Weak Solar Energetic Particle Events