Connecting theory of plasmoid-modulated reconnection to observations of solar flares

Abstract

The short timescale of the solar flare reconnection process has long proved to be a puzzle. Recent studies suggest the importance of the formation of plasmoids in the reconnecting current sheet, with quantifying the aspect ratio of the width to length of the current sheet in terms of a negative power $\alpha$ of the Lundquist number, i.e. $S^{-\alpha }$, being key to understanding the onset of plasmoids formation. In this paper we make the first application of theoretical scalings for this aspect ratio to observed flares to evaluate how plasmoid formation may connect with observations. We find that for three different flares showing plasmoids a range of $\alpha$ values of $\alpha =0.27$ to $0.31$. The values in this small range implies that plasmoids may be forming before the theoretically predicted critical aspect ratio ($\alpha =1/3$) has been reached, potentially presenting a challenge for the theoretical models.

6 pages, 1 figure, 1 table. Published Open Access version (https://doi.org/10.1017/exp.2022.23)

References in corpus (7)

• Instability of current sheets and formation of plasmoid chains
• General Theory of the Plasmoid Instability
• Plasmoid Instability in Evolving Current Sheets and Onset of Fast Reconnection
• Magnetohydrodynamic shocks in and above post-flare loops: two-dimensional simulation and a simplified model
• Observational Evidence of Particle Acceleration Associated with Plasmoid Motions
• Statistical Study of Plasmoids associated with post-CME Current Sheet
• Connecting theory of plasmoid-modulated reconnection to observations of solar flares

Cited by in corpus (1)

• Connecting theory of plasmoid-modulated reconnection to observations of solar flares