Quantitative Examination of a Large Sample of Supra-Arcade Downflows in Eruptive Solar Flares

TL;DR

This study provides a comprehensive statistical analysis of supra-arcade downflows in eruptive solar flares, using semi-automatic detection to measure their properties and inform reconnection models.

Contribution

It introduces a large, systematically analyzed catalog of SADs and SADLs, applying semi-automatic detection to quantify their physical parameters.

Findings

Measured velocities, accelerations, and areas of SADs and SADLs.

Estimated magnetic flux and reconnection rates.

Analyzed the implications for magnetic reconnection models.

Abstract

Sunward-flowing voids above post-coronal mass ejection (CME) flare arcades were first discovered using the soft X-ray telescope (SXT) aboard Yohkoh and have since been observed with TRACE (extreme ultra-violet (EUV)), SOHO/LASCO (white light), SOHO/SUMER (EUV spectra), and Hinode/XRT (soft X-rays (SXR)). Supra-arcade downflow (SAD) observations suggest that they are the cross-sections of thin flux tubes retracting from a reconnection site high in the corona. Supra-arcade downflowing loops (SADLs) have also been observed under similar circumstances and are theorized to be SADs viewed from a perpendicular angle. Previous studies have presented detailed SAD observations for a small number of flares. In this paper we present a substantial SADs and SADLs flare catalog. We have applied semi-automatic detection software to several of these events to detect and track individual downflows thereby providing statistically significant samples of parameters such as velocity, acceleration, area, magnetic flux, shrinkage energy, and reconnection rate. We discuss these measurements, how they were obtained, and potential impact on reconnection models.