Estimation of Reconnection Flux using Post-eruption Arcades and Its Relevance to 1-au Magnetic Clouds

TL;DR

This paper introduces a new method to estimate flare reconnection flux from post-eruption arcades using EUV images, demonstrating strong agreement with previous methods and linking it to magnetic cloud flux at 1 AU.

Contribution

The paper presents a novel arcade-based approach to compute reconnection flux, validated against flare-ribbon estimates and correlated with magnetic cloud flux at 1 AU.

Findings

Arcade method agrees well with flare-ribbon method (ΦrA ≈ ΦrR).

Reconnection flux correlates with magnetic cloud poloidal flux (ΦP).

Supports the flux rope formation via flare reconnection process.

Abstract

We report on a new method to compute the flare reconnection (RC) flux from post-eruption arcades (PEAs) and the underlying photospheric magnetic fields. In previous works, the RC flux has been computed using cumulative flare ribbon area. Here we obtain the RC flux as half of that underlying the PEA associated with the eruption using an image in EUV taken after the flare maximum. We apply this method to a set of 21 eruptions that originated near the solar disk center in Solar Cycle 23. We find that the RC flux from the arcade method ({\Phi}rA) has excellent agreement with that from the flare-ribbon method ({\Phi}rR) according to: {\Phi}rA = 1.24({\Phi}rR)^0.99. We also find {\Phi}rA to be correlated with the poloidal flux ({\Phi}P) of the associated magnetic cloud at 1 AU: {\Phi}P = 1.20({\Phi}rA)^0.85. This relation is nearly identical to that obtained by Qiu et al. (Astrophys. J. 659, 758, 2007) using a set of only nine eruptions. Our result supports the idea that flare reconnection results in the formation of flux rope and PEA as a common process.