Solar proton event of April 16, 1970 1. Features in interplanetary space and in the magnetosheath

Journal Article · Fri Jul 01 04:00:00 EDT 1977 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA082i019p02657· OSTI ID:7218497

Palmer, I D; Higbie, P R; Hones, Jr, E W

A description is given of the solar particle event of April 16, 1970, as recorded by two Vela satellites which were in the vicinity of the earth's bow shock at 18 R/sub E/. Comparison with Explorer 35 in lunar orbit indicates that the early time profile of the event was due to a spatial structure convected past the earth, and the orientation of the convected front is deduced. Anisotropies and pitch angle distributions of energetic protons are obtained from a 32-point sampling of the particle flux over the celestial sphere with a time resolution of 1 min. The net flow patterns inferred in interplanetary space reveal two reversals in the north-south component, in general alignment with the magnetic field, neither was accompanied by a magnetic field reversal. Novel features of the pitch angle distributions recorded at proton energies of approx. =1 MeV included (1) a narrow forward peak at 0degree pitch angle observed in interplanetary space and accompanied by a smaller backscatter peak (we conclude that the forward peak is a real interplanetary effect uncontaminated by the presence of the bow shock). (2) accompanying this forward peak, a difference in the omnidirectional intensities at Vela 6B and at Vela 5B, of a factor of approx. =3, when these satellites were situated in the solar wind and in the magnetosheath, respectively, (3) a pronounced depression over approximately one hemisphere which was recorded by both Vela 6B and 5B when each was in the magnetosheath and which represents a distortion of the interplanetary pitch angle distribution due to propagation of particles into the magnetosheath.

• Research Organization: Oral Roberts University, Tulsa, Oklahoma 74102
• OSTI ID: 7218497
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 82:19; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANISOTROPY
BARYONS
ELEMENTARY PARTICLES
ENERGY RANGE
FERMIONS
HADRONS
INCLINATION
INTERPLANETARY MAGNETIC FIELDS
INTERPLANETARY SPACE
MAGNETIC FIELDS
MAGNETOSHEATH
MEV RANGE
NUCLEONS
PROTONS
RADIATIONS
SOLAR ACTIVITY
SOLAR PARTICLES
SOLAR PROTONS
SOLAR RADIATION
SOLAR WIND
SPACE
STELLAR RADIATION