Interplanetary scattering mean free path: Collisionless wave-damping effects

Journal Article · Mon Oct 01 04:00:00 EDT 1984 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/162517· OSTI ID:6000466

Davila, J M; Scott, J S

Waves with small wavelengths are responsible for the scattering of particles with small values of ..mu.. (where ..mu.. is the cosine of the particle pitch angle). However, these waves are strongly damped in a thermal plasma by the process of collisionless cyclotron damping. This damping severely reduces theamplitude of the waves at small wavelengths and, in turn, results in a severely reduced scattering rate near ..mu.. = 0. This effect allows the mean free path for some particles to be much longer than the value estimated from standard quasi-linear theory. To demonstrate this point, a specific model for the observed interplanetary magnetic turbulence spectrum is chosen which is consistent with current observational constraints and also reflects the effects of collisionless wave damping. The consequences of these assumptions for the calculation of the interplanetary mean free path are explored. Specific predictions of the theory regarding the propagation of protons are best described by considering three separate kinetic energy regimes.

• Research Organization: Laboratory for Astronomy and Solar Physics, NASA/Goddard Space Flight Center
• OSTI ID: 6000466
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 285:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640101* -- Astrophysics & Cosmology-- Cosmic Radiation
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC ELECTRONS
COSMIC PHOTONS
COSMIC RADIATION
COSMIC RAY PROPAGATION
DAMPING
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
INTERPLANETARY SPACE
IONIZING RADIATIONS
LEPTONS
MAGNETIC FIELDS
MASSLESS PARTICLES
MEAN FREE PATH
PHOTONS
RADIATIONS
RESONANCE
SCATTERING
SPACE
TURBULENCE
WAVE PROPAGATION