Microwave Negative Bursts as Indications of Reconnection between Eruptive Filaments and Large-Scale Coronal Magnetic Environment

TL;DR

This paper investigates microwave negative bursts caused by plasma ejections during solar eruptions, highlighting their connection to magnetic reconnection between eruptive filaments and the coronal environment.

Contribution

It provides a systematic analysis of negative burst events, distinguishing between normal and anomalous filament eruptions, and proposes a reconnection-based scenario for anomalous cases.

Findings

Negative bursts correlate with filament eruptions.

Anomalous eruptions involve filament disintegration and large-scale dispersal.

Reconnection may explain anomalous eruption phenomena.

Abstract

Low-temperature plasma ejected in solar eruptions can screen active regions as well as quiet solar areas. Absorption phenomena can be observed in microwaves as 'negative bursts' and in different spectral domains. We analyze two very different recent events with such phenomena and present an updated systematic view of solar events associated with negative bursts. Related filament eruptions can be normal, without essential changes of shape and magnetic configuration, and 'anomalous'. The latter are characterized by disintegration of an eruptive filament and dispersal of its remnants as a cloud over a large part of solar disk. Such phenomena can be observed as giant depressions in the He II 304 A line. One of possible scenarios for an anomalous eruption is proposed in terms of reconnection of filament's internal magnetic fields with external large-scale coronal surrounding.