Energetic particle diffusion coefficients upstream of quasi-parallel interplanetary shocks

Journal Article · Thu Jun 01 00:00:00 EDT 1989 · Journal of Geophysical Research; (USA)

DOI:https://doi.org/10.1029/JA094iA06p06552· OSTI ID:5948537

Tan, L C; Mason, G M; Gloeckler, G; Ipavich, F M ^[1]

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1. Univ. of Maryland, College Park (USA)

The authors have analyzed the properties of {approximately} 30 to 130-keV/e protons and alpha particles upstream of six quasi-parallel interplanetary shocks that passed by the ISEE 3 spacecraft during 1978-1979. The measurements were performed with the University of Maryland/Max Planck Institute ULECA sensor. They deduced the energetic particle diffusion coefficients, {kappa}{sub {parallel}}, by calculating the difference between the bulk flow speed of the particles and their estimated scattering center speeds in the spacecraft frame and relating this to the particle spatial intensity gradients upstream. This calculation yielded diffusion coefficients for each 2-min interval in the last {approximately} 15 min before shock passage, when the particle intensities were high. Comparing these diffusion coefficients in detail with the theory of Lee, they find that upstream of the shock the A/Q dependences of {kappa}{sub {parallel}} for alphas and protons agrees well with the theory. Upstream of the shock, {kappa}{sub {parallel}} often increases with distance, as predicted by Lee's theory, although the details of this increase do not agree with the theory. At the shock front itself they find excellent agreement between theory and observation for (1) the velocity dependence of {kappa}{sub {parallel}}, and, (2) the dependence of {kappa}{sub {parallel}} on the magnitude of the proton distribution function.

• OSTI ID: 5948537
• Journal Information: Journal of Geophysical Research; (USA), Vol. 94:A6; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
INTERPLANETARY SPACE
NEUTRAL-PARTICLE TRANSPORT
PROTON TRANSPORT
COMPARATIVE EVALUATIONS
DIFFUSION
DISTRIBUTION FUNCTIONS
SATELLITES
SCATTERING
SHOCK WAVES
SOLAR ALPHA PARTICLES
SOLAR PARTICLES
SOLAR PROTONS
SOLAR WIND
TEST PARTICLES
ALPHA PARTICLES
BARYONS
CHARGED PARTICLES
CHARGED-PARTICLE TRANSPORT
ELEMENTARY PARTICLES
FERMIONS
FUNCTIONS
HADRONS
NUCLEONS
PROTONS
RADIATION TRANSPORT
RADIATIONS
SOLAR ACTIVITY
SOLAR RADIATION
SPACE
STELLAR RADIATION
640104* - Astrophysics & Cosmology- Solar Phenomena