Evolution of Solar Magnetic Field and Associated Multi-wavelength Phenomena: Flare events on 20 November 2003

TL;DR

This study investigates two homologous solar flare events on 20 November 2003, analyzing multi-wavelength data to understand magnetic reconnection, filament interactions, and associated coronal mass ejections, revealing the dynamics of energy release and magnetic field evolution.

Contribution

It provides detailed multi-wavelength analysis of filament interactions and reconnection processes leading to CMEs, highlighting the role of sunspot rotation and magnetic helicity injection.

Findings

Reconnection occurred during filament interaction, causing maximum flare emission.

The first event produced a narrow, slow CME; the second resulted in a fast halo CME.

Magnetic energy was confirmed to drive CME expansion and propagation.

Abstract

We analyze H-alpha images, soft X-ray profiles, magnetograms, extreme ultra-violet images and radio observations of two homologous flare events (M1.4/1N and M9.6/2B) on 20 November 2003 in the active region NOAA 10501 and study properties of reconnection between twisted filament systems, energy release and associated launch of coronal mass ejections (CMEs). During both events twisted filaments observed in H-alpha approached each other and initiated the flare processes. However, the second event showed the formation of cusp as the filaments interacted. The rotation of sunspots of opposite polarities, inferred from magnetograms likely powered the twisted filaments and injection of helicity. Along the current sheet between these two opposite polarity sunspots, the shear was maximum, which could have caused the twist in the filament. At the time of interaction between filaments, the reconnection took place and flare emission in thermal and non-thermal energy ranges attained the maximum. The radio signatures revealed the opening of field lines resulting from reconnection. The H-alpha images and radio data provide the inflow speed leading to reconnection and the scale size of particle acceleration region. The first event produced a narrow and slow CME, whereas the later one was associated with a fast full halo CME. The halo CME signatures observed between Sun and Earth using white-light and scintillation images and in-situ measurements indicated the magnetic energy utilized in the expansion and propagation. The magnetic cloud signature at the Earth confirmed the flux rope ejected at the time of filament interaction and reconnection.