Local and global scattering properties of the interplanetary medium obtained from Solar Energetic Particles (SEPs)

Conference · Thu Jun 01 04:00:00 EDT 1995

OSTI ID:266933

Wibberenz, G; Hatzky, R; Bieber, J W

Solar energetic particles can be used as probes for the turbulence level in the interplanetary medium. It is of general interest to compare the LOCAL scattering properties near an observer with GLOBAL properties which characterize the average scattering along the magnetic field. The authors discuss various methods by which the scattering conditions can be determined: (1) overall fits of observed particle intensities and anisotropies to a transport model; (2) evaluation of the steady-state pitch angle distribution; and (3) suitably normalized angular distributions during the intensity maximum of a particle event. Energetic particle data from HELIOS 1/2 are analyzed, and the mean free paths obtained with the different methods are compared with each other. As a result one can state: (1) for a number of solar particle events the radial mean free path is essentially constant between the Sun and Helios; and (2) large variations in the degree of scattering exist from one event to the other. These results indicate the existence of `regimes` where the amount of particle scattering is relatively constant over extended regions in radius and azimuth, but with marked differences from one regime to the other.

• Research Organization: Jet Propulsion Lab., Pasadena, CA (United States)
• OSTI ID: 266933
• Report Number(s): N--96-24651; NASA-CR--199940; JPL-PUBL--95-13; NAS--1.26:199940; NIPS--95-06571; CONF-9506256--
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ANISOTROPY
AZIMUTH
INTERPLANETARY SPACE
MATHEMATICAL MODELS
MEAN FREE PATH
SCATTERING
SOLAR PARTICLES
TURBULENCE