Proton energy spectra at the sun in the solar cosmic-ray events on 1978 May 7 and 1984 February 16

Journal Article · Tue May 01 04:00:00 EDT 1990 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/168763· OSTI ID:6690976

Lockwood, J A; Debrunner, H; Flueckiger, E O; Graedel, H ^[1]

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1. New Hampshire Univ., Durham (USA) Bern Universitaet (Switzerland)

The solar proton differential energy spectra at the sun as a function of rigidity have been deduced for the solar cosmic-ray events on May 7, 1978 and February 16, 1984. Proton data were used from the IMP spacecraft for energies from about 20-500 MeV and from the worldwide network of neutron monitors for energies greater than 500 MeV. Since these events were characterized by essentially scatter-free propagation in the interplanetary medium, the solar proton energy spectra observed at earth were extrapolated back to the sun to obtain the source spectra. It was found that the relative solar proton spectra at the sun varied with time. They could be fitted by dJ/dE = A x P exp -delta x exp (-P/P0), where delta is about 4-5 and P0 is not less than 5000 MV. These results are interpreted in terms of the diffusive coronal shock acceleration model of Ellison and Ramaty (1985), obtaining shock sizes of greater than about 10 to the 9th cm and shock compression ratios of 1.7-2.1. The solar energy spectra predicted by stochastic acceleration do not fit the relative proton energy spectra at the sun for the two events considered. 16 refs.

• OSTI ID: 6690976
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 355; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCELERATION
ASTRONOMY
BARYONS
ELEMENTARY PARTICLES
ENERGY SPECTRA
FERMIONS
HADRONS
NUCLEONS
PROTONS
RADIATIONS
SATELLITES
SHOCK WAVES
SOLAR ACTIVITY
SOLAR FLARES
SOLAR PARTICLES
SOLAR PROTONS
SOLAR RADIATION
SPECTRA
STELLAR RADIATION
STOCHASTIC PROCESSES