Can Type III Radio Storms be a Source of Seed Particles to Shock Acceleration?

TL;DR

This paper investigates whether Type III radio storms can supply seed particles for shock acceleration, analyzing two CME events and their associated SEP activity to understand the role of these storms in particle acceleration.

Contribution

It proposes that Type III radio storms may accelerate ions that serve as seed particles for CME-driven shock acceleration, a novel insight into SEP event origins.

Findings

Type III storms are associated with intense SEP events.

Presence of seed particles influences SEP intensity.

Type III storms may contribute to seed particle populations.

Abstract

An intense type III radio storm has been disrupted by a fast halo coronal mass ejection (CME) on 2000 April 4. The CME is also associated with a large solar energetic particle (SEP) event. The storm recovers after about10 hrs. We identified another CME that occurs on 2003 November 11 with similar CME properties but there is no type III storm in progress. The 2003 November 11 CME is also not associated with an SEP event above the background (less than 2 pfu), whereas the one with type III storm has an intense SEP event (about 56 pfu). One of the factors affecting the intensity of SEP events is the presence of seed particles that are accelerated by CME-driven shocks. We suggest that the type III storm source, which accelerates electrons to produce the storm, also accelerates ions that serve as seed particles to the CME shock.