The white-light continuum in the impulsive phase of a solar flare

TL;DR

This paper investigates the IR/visible/VUV continuum emission during the impulsive phase of a solar flare, revealing its spectral characteristics and energetic significance using TRACE observations.

Contribution

It provides new insights into the spectral energy distribution and origin of the continuum emission in the impulsive phase of solar flares.

Findings

Continuum dominates the radiant energy during the impulsive phase.

Spectral analysis shows a Balmer jump indicating an optically thin origin.

Elevated temperature and ionization levels are observed in the emission region.

Abstract

We discuss the IR/visible/VUV continuum emission of the impulsive phase of a solar flare, using TRACE UV and EUV images to characterize the spectral energy distribution. This continuum has been poorly observed but dominates the radiant energy energetically. Recent bolometric observations of solar flares furthermore point to the impulsive phase as the source of a major fraction of the radiant energy. This component appears to exhibit a Balmer jump and thus must originate in an optically thin region above the quiet photosphere, with an elevated temperature and strong ionization.