Focused transport of energetic particle along magnetic field lines draped around a coronal mass ejection

Journal Article · Sat Feb 01 00:00:00 EST 1992 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/91JA02699· OSTI ID:5439592

Tan, L C; Mason, G M; Ipavich, F M ^[1]; Lee, M A ^[2]; Klecker, B ^[3]

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1. Univ. of Maryland, College Park (United States)
2. Univ. of New Hampshire, Durham (United States)
3. Max-Planck-Inst. fuer Physik and Astrophysik, Garching (West Germany)

The transport of particles in interplanetary space can be determined by adiabatic focusing of particle pitch angle distributions under conditions when the ratio of the particle scattering mean free path to the magnetic field focusing length, {lambda}/L, is {approximately}1. Since for the average. Archimedean spiral field configuration, L {approximately} 1 AU at Earth orbit, the only reported events dominated by focusing are those nearly scatter-free events where {lambda} {approximately}1 AUA. However, if the interplanetary magnetic field is distorted so that the focusing length L is small, then even if the interplanetary scattering mean free path were small, focused transport would be expected to dominate, since {lambda}/L would still be {approximately}1. The authors present evidence for such an event, obtained with observations of {approximately}0.1-1 MeV nucleon{sup {minus}1} protons and alpha particles obtained with the University of Maryland/Max-Planck-Institut experiment on the ISEE 3 spacecraft during the decay phase of the June 6, 1979, solar particle event. During the early portion of the decay phase of this event, interplanetary magnetic field lines were apparently draped around a coronal mass ejection, leading to a small focusing length L on the western flank where ISEE 3 was located. They observed a period of very slow decrease of particle intensity, along with large sunward anisotropy in the solar wind frame, which are inconsistent with predictions of the standard Fokker-Planck equation models for diffusive transport; however, they are able to fit the observations assuming that focused transport dominates and that the particle pitch angle scattering is isotropic.

• OSTI ID: 5439592
• Journal Information: Journal of Geophysical Research; (United States), Vol. 97:A2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
INTERPLANETARY SPACE
CHARGED-PARTICLE TRANSPORT
SOLAR PARTICLES
ACCELERATION
SCATTERING
EXPLORER SATELLITES
INTERPLANETARY MAGNETIC FIELDS
MAGNETIC FIELD CONFIGURATIONS
MASS TRANSFER
MEAN FREE PATH
SOLAR CORONA
SPATIAL DISTRIBUTION
ATMOSPHERES
DISTRIBUTION
MAGNETIC FIELDS
RADIATION TRANSPORT
RADIATIONS
SATELLITES
SOLAR ATMOSPHERE
SOLAR RADIATION
SPACE
STELLAR ATMOSPHERES
STELLAR CORONAE
STELLAR RADIATION
661320* - Auroral
Ionospheric
& Magnetospheric Phenomena- (1992-)