Flare magnetic reconnection and relativistic particles in the 2003 October 28 event

TL;DR

This study analyzes a major 2003 solar flare, linking magnetic reconnection processes to the acceleration of relativistic particles and their detection at Earth, highlighting the timing and possible mechanisms involved.

Contribution

It provides an integrated analysis of multi-wavelength data to connect magnetic reconnection with relativistic particle acceleration during a significant solar flare.

Findings

Magnetic reconnection electric field correlates with high-energy emissions.

Neutron emission precedes proton and electron injection, indicating a delay in particle acceleration.

CME-driven shocks may influence the delayed phase of solar energetic particles.

Abstract

An X17.2 solar flare occurred on 2003 October 28, accompanied by multi-wavelength emissions and a high flux of relativistic particles observed at 1AU. We present the analytic results of the TRACE, SOHO, RHESSI, ACE, GOES, hard X-ray (INTEGRAL satellite), radio (Onderejov radio telescope), and neutron monitor data. It is found that the inferred magnetic reconnection electric field correlates well with the hard X-ray, gamma-ray, and neutron emission at the Sun. Thus the flare's magnetic reconnection probably makes a crucial contribution to the prompt relativistic particles, which could be detected at 1 AU. Since the neutrons were emitted a few minutes before the injection of protons and electrons, we propose a magnetic-field evolution configuration to explain this delay. We do not exclude the effect of CME-driven shock, which probably plays an important role in the delayed gradual phase of solar energetic particles.