The relative abundances and energy spectra of solar-flare-accelerated deuterium, tritium, and helium-3

Abstract

view Abstract Citations (44) References (30) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The relative abundances and energy spectra of solar-flare-accelerated deuterium, tritium, and helium-3. Anglin, J. D. Abstract The relative abundances and energy spectra of 2H, 3H, and 3He have been studied in energetic solar particle events with the University of Chicago IMP-S charged-particle telescope. The outstanding result of these observations is the remarkable scarcity of 2H and 3H in several flares which have extremely large abundances of 3He. For example, we find in the 1970 July 30 solar particle event F(3He( He) = 0.54 + 0.09 between 10.5 and 22.1 MeV nucleon-', while at the same time F(2H/3He) < 0.05. (The symbol F is used to represent the ratio of the integral fluxes of two species in the same energy-per-nucleon interval.) Since these normally rare isotopes are thought to be the products of 4He fragmentation during particle acceleration, it is not clear how one could be observed without the others. Yet the data clearly show that 2H and 3H are extremely rare. In a large sum composed of 75 solar flare events, we find F(2H!'H) = (5.4 I 2.4) x 10- between 10.5 and 13.5 MeV nucleon-'. A detailed comparison of these observations with different nuclear production models is undertaken in this paper. It is shown that neither the isotropic production models developed in this paper, nor the model of Ramaty and Kozlovsky, in which 3He is preferentially produced in the backward direction by a beam of protons directed downward into the photosphere, provides an adequate explanation of all the observational data. Subject headings: abundances, solar cosmic rays - deuterium - flares, solar - nuclear reactions Publication: The Astrophysical Journal Pub Date: June 1975 DOI: 10.1086/153651 Bibcode: 1975ApJ...198..733A Keywords: Abundance; Deuterium; Energy Spectra; Particle Acceleration; Solar Cosmic Rays; Solar Flares; Astronomical Models; Energy Dissipation; Kinetic Energy; Solar Physics full text sources ADS |