Direct observation of high-speed plasma outflows produced by magnetic reconnection in solar impulsive events

TL;DR

This paper presents the first spectroscopic observation of high-speed plasma outflows caused by magnetic reconnection during solar impulsive events, confirming theoretical predictions with measured velocities and magnetic field estimates.

Contribution

It provides the first direct spectroscopic evidence of hot plasma outflows in the solar corona during magnetic reconnection events, with quantitative velocity and magnetic field measurements.

Findings

Outflow speeds between 900-3500 km/s consistent with Alfvenic predictions

Observation of sequential blue- and red-shifts indicating plasma jets

Estimated magnetic field strength near reconnection site: 19-37 Gauss

Abstract

Spectroscopic observations of a solar limb flare recorded by SUMER on SOHO reveal, for the first time, hot fast magnetic reconnection outflows in the corona. As the reconnection site rises across the SUMER spectrometer slit, significant blue- and red-shift signatures are observed in sequence in the Fe XIX line, reflecting upflows and downflows of hot plasma jets, respectively. With the projection effect corrected, the measured outflow speed is between 900-3500 km/s, consistent with theoretical predictions of the Alfvenic outflows in magnetic reconnection region in solar impulsive events. Based on theoretic models, the magnetic field strength near the reconnection region is estimated to be 19-37 Gauss.