Observations related to the acceleration, injection, and interplanetary propagation of energetic protons during the solar cosmic ray event on February 16, 1984

Journal Article · Fri Jul 01 04:00:00 EDT 1988 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA093iA07p07206· OSTI ID:7125147

Debrunner, H; Flueckiger, E; Graedel, H; Lockwood, J A; McGuire, R E

Data from the worldwide network of neutron monitors and from the cosmic ray telescopes on IMP 8 have been used to deduce the intensity-time profiles, the anisotropy-time profiles, the energy spectra, and the pitch angle distributions of the solar protons near Earth during the solar cosmic ray event on February 16, 1984. In addition, measurements by particle detectors on the GOES 5 and 6 and ICE spacecraft were used in the analysis. The pronounced anisotropy of the particle fluxes, lasting approx.40 min at relativistic energies and more than 2 hours at approx.75 MeV, shows that the propagation of the solar protons in the interplanetary magnetic field (IMF) was practically scatter-free (mean free path lambdaapprox. >2 AU) and that the injection of the particles into the IMF at the Sun was time-extended. Although the analysis of the onset times of the event as a function of the reciprocal of the proton speeds does not clearly exclude a delta-like acceleration of the flare protons, we infer that the solar protons with 70- to 500-MeV energy were injected into the IMF 4 +- 2 min earlier than the relativistic protons. Proton energy spectra at the Sun over a range from 25 MeV to 10 GeV, as constructed from the solar proton observations at Earth, evolved with time in both amplitude and energy. The time evolution of the energy spectra at the Sun also suggests that the lower-energy protons were accelerated earliest. These observations are consistent with an acceleration of the protons by a coronal shock. copyright American Geophysical Union 1988

• Research Organization: Physikalisches Institut, University of Bern, Bern, Switzerland
• OSTI ID: 7125147
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 93:A7; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCELERATION
ANISOTROPY
BARYONS
ELEMENTARY PARTICLES
ENERGY SPECTRA
FERMIONS
GOES SATELLITES
HADRONS
IMP SATELLITES
INCLINATION
INTERPLANETARY MAGNETIC FIELDS
INTERPLANETARY SPACE
MAGNETIC FIELDS
MEAN FREE PATH
NUCLEONS
PLASMA ACCELERATION
PROTONS
RADIATIONS
SATELLITES
SOLAR ACTIVITY
SOLAR FLARES
SOLAR PARTICLES
SOLAR PROTONS
SOLAR RADIATION
SPACE
SPECTRA
STELLAR RADIATION