Alexei Struminsky

Gather.town id
CME02
Poster Title
CME ACCELERATION IN IMPULSIVE (Х6.9 09.08.2011) AND GRADUAL (M3.7 07.03.2011) SOLAR FLARES
Institution
Space Research Institute. Moscow
Abstract (short summary)
We analyze solar events associated with flares: gradual - M3.7 on March 7, 2011 and impulsive - X6.9 on August 9, 2011. These flares were accompanied by HXR and MW radiation, sustained > 100 MeV gamma radiation, CME with a velocity of ~ 2000 km /s. Estimates of the magnitude and duration of acceleration for CME were obtained from the condition of stitching the assumed uniformly accelerated and observed uniform motion. These estimates indicate that the CME should have accelerated significantly longer than the estimated minimum time. The obtained mean values and duration of CME acceleration do not contradict CME acceleration in two phases - impulsive and prolong, as was directly observed in the events of May 13, 2013 [Gou et al. 2020] and September 10, 2017 [Gopalswamy et al., 2018]. In the cases considered the largest bursts of HXR and MW radiation can be observed both before and during the CME impulsive acceleration (X6.9 flare on August 9, 2011), and after it (M3.7 flare on March 7, 2011). ). This shows that the acceleration processes of charged particles in flares do not depend on the magnitude of the CME acceleration. The CME velocity is high in the corona and interplanetary space, most likely, was determined by a long acceleration on March 7, 2011, but a long deceleration on August 9, 2011.
Plain text (extended) Summary
What secuence of processes on the Sun lead to positive feedback between heating of plasma and acceleration of electrons, heating and motion of plasma resulting in formation of CME and acceleration of protons? We answer this question for the gradual M3.7 flare on 07/03/2011 (Struminsky et al., 2021 in press) and the impulsive X6.9 flare on 09/08/2011 (Sharykin et al., 2015; Struminsky et al., 2020) using information on : plasma heating - SXR (GOES) T, EM dT/dt; plasma motion in flare region - dEM/dt, AIA (SDO), drift of frequencies (1415-245 MHz, RSTN); electron acceleration - microwaves (15.4-2.695 GHz, RSTN), HXR > 150 keV (Anti-Coincidence Shield of Spectrometer on INTEGRAL — ACS SPI); CME position - LASCO/SOHO (C2-C3); proton acceleration - γ-rays > 100 MeV (FermiLAT, Ackermann et al., 2014; Share et al., 2018), solar proton events (protons > 100 MeV, ACS SPI).

Acceleration of non-thermal electrons with soft spectrum at heights ~105 km (fp~245 MHz, ne < 7.4·108 cm-3), electrons heat surrounding plasma, EM is practically constant, the magnetic flux rope is confined, the electron spectrum becomes harder.

The acceleration site moves from (1) to (2), a new acceleration site (3) may appear by chance, T is increasing. If the acceleration site (3) is close to the chromosphere then the chromospheric evaporation starts (the case of 09/08/2011).

The acceleration of CME is going up to ~3.5·105km due to plasma expansion. Further the CME (plasma above closed field lines of active region including the magnetic flux rope) moves with conctant velocity or with small acceleration/deceleration. Particles (electrons < 10 MeV, protons > 100 MeV) are accelerating below the CME in (4).

URL
astruminsky@gmail.com
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