HXR emission from an activated flux rope and subsequent evolution of an eruptive long duration solar flare.

摘要: In this paper, we present a comprehensive study of the evolutionary phases major M6.6 long duration event (LDE) with special emphasize on its pre-flare phase. The occurred in NOAA 12371 2015 June 22. A remarkable aspect was an active phase lasting for about hour during which hot EUV coronal channel build-up stage and displayed co-spatial hard X-ray (HXR) emission up to energies 25 keV. As such, is first evidence HXR channel. magnetic field configuration based NLFFF modeling clearly exhibited flux rope (MFR) oriented along polarity inversion line (PIL) We observed significant changes AR's photospheric extended period $\approx$42 hours form rotation sunspots, moving features, cancellation PIL. Prior flare onset, MFR underwent slow rise ($\approx$14 km s$^{-1}$) $\approx$12 min attribute faster activation by tether-cutting reconnection occurring at multiple locations itself. sudden transition kinematic evolution from fast ($\approx$109 s$^{-1}$ acceleration $\approx$110 m s$^{-2}$) precisely divides impulsive flare, points toward feedback process between early dynamics eruption strength reconnection.