Further Evidences of Multiple Acceleration of Solar Energetic Particles

1. Further Evidences of Multiple Acceleration of Solar Energetic Particles • A.B. Struminskya,b,c and I.V. Zimovetsa,b • (a) Space Research Institute, Profsoyuznaya st., 84/32, Moscow, 117997, Russia • (b) Moscow Institute of Physics and Technology, Dolgoprudny, Moscow region, Russia • (c) IZMIRAN, Troitsk, Moscow region, 142092, Russia

2. INTRODUCTION • The prolonged neutral emission registered by different instruments in June 1991, till the solar extreme events (SEE) of October 2003, was a sole fact proving existence of >100 MeV protons deep in the Sun during hours. • This report summarizes further evidences of multiple acceleration of protons based on observations of SEE’s in 2003 and 2005. • The count rate of the Anti-Coincidence System (ACS) of SPectrometer on INTEGRAL (SPI), which is sensitive to primary γ-rays above ~100 keV as well as to charged particles and secondary γ-rays from interaction in the telescope and satellite structure, • The ACS count rate was above background for a rather long time during the events of 28 October 2003, 20 January 2005 and 07 September 2005, (i.e. does not contradict to the possibility of prolonged solar -ray emission) possibly indicating different acceleration episodes, the source of solar energetic particles extended in space and time. • Two episodes of the prolonged neutron production might occur in the solar atmosphere on 28 October 2003. • The proton intensities time profiles observed on 20 January 2005 provide evidences for two episodes of proton acceleration separated by about 30 minutes. • The γ-ray event of 07 September 2005 (S06E89), observed by INTEGRAL well before the solar proton onset, clearly shows several γ-ray peaks and should be crucial for interpretation of previous events.

3. ACS counts – GOES protons, 07 September 2005

4. 28 October 2003 – 07 September 2005

5. ACS counts – GOES protons,20 January 2005