Solar flares with sustained gamma-ray emission and some characteristics of high-energy proton fluxes

We describe the characteristics of long-term gamma fluxes with quantum energies >100 MeV, obtained from Fermi/LAT data during the impulsive phase of the most energetic flare phenomena. We compare GOES data on proton fluxes with energies >500 MeV with Fermi/LAT data on gamma fluxes for the period 2010–2018. The results of the analysis of all data obtained on 32 gamma-ray flares from the Fermi/LAT catalog show that the flare phenomena can be classified into three different types: type 1 — gamma fluxes accompanied by energetic proton fluxes; type 2 — gamma rays recorded in the absence of increases in proton fluxes; type 3 — gamma fluxes not recorded during observed increases in energetic proton fluxes. The burst character of energy release in the hard X-ray range was noted in some flares.