2H and 3He Isotopes in Solar Flares, According to the PAMELA Data for 2006–2014

Results are presented for the first time from the PAMELA orbital experiment of 2006–2014. Observations record 2H isotopes with energies above ~50 MeV/nucleon and 3He isotopes with energies above ~90 MeV/nucleon in solar flares. Time-of-flight analysis of nuclei that have rigidities known from orbital experiments with the scintillation telescope of the PAMELA magnetic spectrometer is used for isotope selection, along with data on their ionization losses in the strip detectors of the tracker. The spectra of 1Н and 4Не in solar cosmic rays are used in GEANT4 simulation of the 2H and 3Не nuclei generation in solar matter to assess the spatial scale of the region of isotope generation. Additional acceleration of the 2H and 3Не nuclei during flares is likely revealed.