Responsibility of a Filament Eruption for the Initiation of a Flare, CME, and Blast Wave, and its Possible Transformation into a Bow Shock

Abstract

Multi-instrument observations of two filament eruptions on 24 February and 11 May 2011 suggest the following updated scenario for eruptive flare, CME and shock wave evolution. An initial destabilization of a filament results in stretching out of magnetic threads belonging to its body and rooted in the photosphere along the inversion line. Their reconnection leads to i) heating of parts of the filament or its environment, ii) initial development of the flare arcade cusp and ribbons, and iii) increasing similarity of the filament to a curved flux rope and its acceleration. Then the pre-eruption arcade enveloping the filament gets involved in reconnection according to the standard model and continues to form the flare arcade and ribbons. The poloidal magnetic flux in the curved rope developing from the filament progressively increases and forces its toroidal expansion. This flux rope impulsively expands and produces an MHD disturbance, which rapidly steepens into a shock. The shock passes through the arcade expanding above the filament and then freely propagates ahead of the CME like a decelerating blast wave for some time. If the CME is slow, then the shock eventually decays. Otherwise, the frontal part of the shock changes into the bow-shock regime. This was observed for the first time in the 24 February 2011 event. When reconnection ceases, the flux rope relaxes and constitutes the CME core-cavity system. The expanding arcade develops into the CME frontal structure. We also found that reconnection in the current sheet of a remote streamer forced by the shock's passage results in a running flare-like process within the streamer responsible for

Radio, Hard X-Ray, and Gamma-Ray Emissions Associated with a Far-Side Solar Event

“…As demonstrated in our preceding studies (e.g. Grechnev et al, 2015Grechnev et al, , 2016, the most probable source of a narrow-band Type II emission is a streamer. The shock crossing the streamer deforms the plasma flow in the vicinity of its current sheet that induces a flare-like process running along the streamer together with the intersection point.…”

Development and Parameters of a Non-Self-Similar CME Caused by the Eruption of a Quiescent Prominence

“…Pursuing reliability of the kinematic measurements, we endeavor to reveal possible changes in the CME shape and structure around presumable acceleration episodes. To facilitate their comparison at different times, we compensate for the CME expansion by resizing the images according to the measured kinematics, in which the CME appears static (Grechnev et al, 2014b(Grechnev et al, , 2015(Grechnev et al, , 2016. This method appears to be the most appropriate so far to assess the measurement accuracy.…”

Correlation of near-Earth proton enhancements >100 MeV with parameters of solar microwave bursts

“…Скорости, перечисленные в каталоге КВМ, измерены по самой быстрой детали, и поэтому для быстрых КВМ значения скорости относятся, ве-роятнее всего, непосредственно к ударным волнам [Ciaravella, 2006;Grechnev et al, 2013aGrechnev et al, , 2014Grechnev et al, , 2015bKwon et al, 2014Kwon et al, , 2015. Скорости КВМ известны для 39 СПС из нашего списка.…”

“…Нами установлена более тесная, чем считалось ранее, взаимосвязь между развитием эруптивных вспышек и возбуждением ударных волн [Grechnev et al, 2013a[Grechnev et al, , 2015b. Следо-вательно, традиционное противопоставление уско-рения частиц ударной волной и во вспышке может быть не вполне правомерным.…”