NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
The telegraph equation in charged particle transportWe present a new derivation of the telegraph equation which modifies its coefficients. First, an infinite order partial differential equation is obtained for the velocity space solid angle-averaged phase-space distribution of particles which underwent at least a few collisions. It is shown that, in the lowest order asymptotic expansion, this equation simplifies to the well-known diffusion equation. The second-order asymptotic expansion for isotropic small-angle scattering results in a modified telegraph equation with a signal propagation speed of v(5/11) exp 1/2 instead of the usual v/3 exp 1/2. Our derivation of a modified telegraph equation follows from an expansion of the Boltzmann equation in the relevant smallness parameters and not from a truncation of an eigenfunction expansion. This equation is consistent with causality. It is shown that, under steady state conditions in a convecting plasma, the telegraph equation may be regarded as a diffusion equation with a modified transport coefficient, which describes a combination of diffusion and cosmic-ray inertia.
Document ID
19930039986
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Gombosi, T. I.
(Michigan Univ. Ann Arbor, United States)
Jokipii, J. R.
(NASA Headquarters Washington, DC United States)
Kota, J.
(Arizona Univ. Tucson, United States)
Lorencz, K.
(Michigan Univ. Ann Arbor, United States)
Williams, L. L.
(Arizona Univ. Tucson, United States)
Date Acquired
August 16, 2013
Publication Date
January 20, 1993
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 403
Issue: 1
ISSN: 0004-637X
Subject Category
Plasma Physics
Accession Number
93A23983
Funding Number(s)
CONTRACT_GRANT: NAGW-2162
CONTRACT_GRANT: NAGW-1366
CONTRACT_GRANT: NSG-7101
CONTRACT_GRANT: NSF ATM-86-18260
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available