Latitudinal gradient of energetic particles in the outer heliosphere during 1985-1986

Journal Article · Wed Apr 01 04:00:00 EST 1987 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA092iA04p03375· OSTI ID:6569728

Decker, R B; Krimigis, S M; Venkatesan, D

We report a measurement of a sustained latitudinal gradient of 70-MeV galactic cosmic ray protons using data from the interplanetary probes Voyager 1 and 2 and the earth-orbiting satellite IMP 8 during a 1-year period from mid-1985 to mid-1986. Starting in early 1985 the intensity of cosmic rays at Voyager 2 began increasing faster than that at Voyager 1. By mid- 1985 the intensity at Voyager 2 (helioradius 17 AU, heliolatitude --0/sup 0/) exceeded and remained higher than that at Voyager 1 (helioradius 24 AU, heliolatitude --26/sup 0/) for at least 14 solar rotations. Using the Voyager 2-IMP 8 data to correct for the radial gradient, we determine an average latitudinal gradient during this period of (-0.53 +- 0.10)% deg/sup -1/ or (-0.38 +- 0.11)% deg/sup -1/ (i.e., intensity decreasing northward of the solar equatorial plane), assuming either a constant radial gradient or one that decreased at an average rate of -0.025% AU/sup -1/ AU/sup -1/, as was the case during 1984, respectively. In addition, we present Voyager data at very low (approx. >30 keV) ion energies which are associated with acceleration at corotating shocks. These ions also exhibit a latitudinal gradient (---3% deg/sup -1/), with lower intensities at higher latitudes, and serve to highlight changes that occurred in the interplanetary medium in early 1985. Copyright American Geophysical Union 1987.

• Research Organization: Applied Physics Laboratory, John Hopkins University, Laurel, Maryland
• OSTI ID: 6569728
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 92:A4; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640101* -- Astrophysics & Cosmology-- Cosmic Radiation
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCELERATION
BARYONS
CHARGED PARTICLES
COSMIC PROTONS
COSMIC RADIATION
DATA ANALYSIS
ELEMENTARY PARTICLES
ENERGY LEVELS
FERMIONS
HADRONS
INTERPLANETARY SPACE
IONIZING RADIATIONS
IONS
NUCLEONS
PROTONS
RADIATIONS
SATELLITES
SHOCK WAVES
SPACE
SPACE VEHICLES
VEHICLES
VOYAGER SPACE PROBES