Magnetic Reconnection Rates and Energy Release in a Confined X-class Flare

Abstract

We study the energy-release process in the confined X1.6 flare that occurred on 22 October 2014 in AR 12192. Magnetic-reconnection rates and reconnection fluxes are derived from three different data sets: space-based data from the Atmospheric Imaging Assembly (AIA) 1600Å filter onboard the Solar Dynamics Observatory (SDO) and ground-based Hα and Ca ii K filtergrams from Kanzelhöhe Observatory. The magnetic-reconnection rates determined from the three data sets all closely resemble the temporal profile of the hard X-rays measured by the Ramaty High Energy Solar Spectroscopic Imager (RHESSI), which are a proxy for the flare energy released into high-energy electrons. The total magnetic-reconnection flux derived lies between 4.1×10 21 Mx (AIA 1600Å) and 7.9 × 10 21 Mx (Hα), which corresponds to about 2 to 4 % of the total unsigned flux of the strong source AR. Comparison of the magnetic-reconnection flux dependence on the GOES class for 27 eruptive events collected from previous studies (covering B to >X10 class flares) reveals a correlation coefficient of ≈ 0.8 in double-logarithmic space. The confined X1.6 class flare under study lies well within the distribution of the eruptive flares. The event shows a large initial separation of the flare ribbons and no separation motion during the flare. In addition, we note enhanced emission at flare-ribbon structures and hot loops connecting these structures before the event starts. These observations are consistent with the emerging-flux model, where newly emerging small flux tubes reconnect with pre-existing large coronal loops.

A Database of Flare Ribbon Properties from the Solar Dynamics Observatory. I. Reconnection Flux

“…We also speculate that due to the Neupert effect (Neupert 1968;Veronig et al 2002), the derived correlation between the reconnection flux and the peak soft X-ray flux will lead to a strong correlation between the peak reconnection flux rate and the peak hard X-ray flux, in agreement with earlier studies of individual events (e.g. Qiu et al 2002;Veronig & Polanec 2015).…”

IRIS, Hinode, SDO, and RHESSI Observations of a White Light Flare Produced Directly by Non-thermal Electrons

“…Previously, , Thalmann et al (2015), and Veronig & Polanec (2015) also investigated this well observed flare using SDO, RHESSI and IRIS. Thalmann et al (2015) and Veronig & Polanec (2015) mainly focused on the magnetic reconnection rates and the RHESSI HXR profiles of this flare, and investigated the relationship between Doppler velocity patterns derived from IRIS Fe XXI and C I and the RHESSI HXR intensity. Those studies showed that the flare energy is injected into high energy electrons, and that they could driver the evaporation flow in the flare.…”

An application of the weighted horizontal magnetic gradient to solar compact and eruptive events

“…It is fair to mention that this AR is rather unusual as being extremely large but, interestingly, CME-poor. AR 12192 has been described well in the literature (Veronig & Polanec, 2015;Jiang et al, 2016;Liu et al, 2016). Here, again, we notice the fol-lowing remarkable properties of the W G M and the distance.…”