Gamma-Ray and High-Energy-Neutron Measurements on CORONAS-F during the Solar Flare of 28 October 2003

Abstract

The solar flare of 28 October 2003 (X17.2/4B) was recorded by the SONG instrument onboard the CORONAS-F satellite. A description of the SONG instrument, its in-orbit operation and the principal data reduction methods used to derive the flare gamma-ray properties are presented. Appreciable gamma-ray emission was observed in the 0.2 -300 MeV energy range. Several time intervals were identified which showed major changes in the intensity and spectral shape of the flare gamma-ray emission. The primary bremsstrahlung proves to be extended to 90 MeV and dominates during 11:02:11 -11:03:50 UT time interval, i.e. at the beginning of the flare impulsive phase. Afterwards, the SONG response was consistent with detection of the pion-decay gamma emission. A sharp increase in the piondecay-generated gamma-ray emission was observed at 11 : 03 : 51 ± 2 s UT, implying a substantial change in the spectrum of accelerated ions, which testified the appearance of protons with energies of > 300 MeV on the Sun. This emission lasted at least 8 -9 min until the end of our measurements. The ion acceleration to high energies was also proved by the detection of neutrons with energies > 500 MeV. It was found that the most efficient acceleration of high-energy protons coincides in time with the highest rate of the magnetic-flux change rate. The maximum gamma-ray flux at 100 MeV was 1.1 × 10 −2 photons cm −2 s −1 MeV −1 , exceeding all the fluxes that have ever been recorded.

Solar Particle Radiation Storms Forecasting and Analysis

“…Various origins were suggested, and a key question was whether such emission would be observed when the accompanying flare was weaker and did not produce impulsive gamma radiation. Detection of such events continued with observations from GAMMA-1 (Akimov et al 1992), the Compton Gamma-Ray Observatory (CGRO) (Mandzhavidze and Ramaty 1992;Kanbach et al 1993;Dunphy et al 1999), GRANAT Vilmer et al 2003), CORONAS-F (Kuznetsov et al 2011;Kuznetsov et al 2014). Around 20 events had been observed then with significant emission above 60 MeV from pion decay radiation (see Lockwood et al 1997;Chupp and Ryan 2009;Vilmer et al 2011 for reviews).…”

X-Ray, Radio and SEP Observations of Relativistic Gamma-Ray Events

“…97, 349, 1993, reproduced with permission ©ESO) key question was whether such emission would be observed when the accompanying flare was weaker and did not produce impulsive gamma radiation. Detection of such events continued with observations from GAMMA-1 (Akimov et al 1992), the Compton Gamma-Ray Observatory (CGRO) (Mandzhavidze and Ramaty 1992;Kanbach et al 1993;Dunphy et al 1999), GRANAT Vilmer et al 2003), CORONAS-F (Kuznetsov et al 2011;Kuznetsov et al 2014). Around 20 events had been observed then with significant emission above 60 MeV from pion decay radiation (see Lockwood et al 1997;Chupp and Ryan 2009;Vilmer et al 2011 for reviews).…”

Fermi Large Area Telescope observations of the Sun: The first ten years

“…During its first nine and a half years in orbit, the Fermi Large Area Telescope (LAT) [1] has detected >30 MeV gamma-ray emission from more than 40 solar flares, nearly 10 times more than EGRET [2] on-board the Compton Gamma-Ray Observatory, GRS [3] on-board the Solar Maximum Mission (SMM) and CORONAS-F [4]. The Fermi detections sample both the impulsive [5] and the long-duration phases [6] including the longest extended emission ever detected (∼20 hours) from the 2012 March 7 GOES X-class flares [7].…”