NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
A Monte Carlo simulation of the effect of ion self-collisions on the ion velocity distribution function in the high-latitude F-regionNon-Maxwellian ion velocity distribution functions have been theoretically predicted and confirmed by observations, to occur at high latitudes. These distributions deviate from Maxwellian due to the combined effect of the E x B drift and ion-neutral collisions. At high altitude and/or for solar maximum conditions, the ion-to-neutral density ratio increases and, hence, the role of ion self-collisions becomes appreciable. A Monte Carlo simulation was used to investigate the behavior of O(+) ions that are E x B-drifting through a background of neutral O, with the effect of O(+) (Coulomb) self-collisions included. Wide ranges of the ion-to-neutral density ratio n(sub i)/n(sub n) and the electrostatic field E were considered in order to investigate the change of ion behavior with solar cycle and with altitude. For low altitudes and/or solar minimum (n(sub i)/n(sub n) less than or equal to 10(exp -5)), the effect of self-collisions is negligible. For higher values of n(sub i)/n(sub n), the effect of self-collisions becomes significant and, hence, the non-Maxwellian features of the O(+) distribution are reduced. The Monte Carlo results were compared to those that used simplified collision models in order to assess their validity. In general, the simple collision models tend to be more accurate for low E and for high n(sub i)/n(sub n).
Document ID
19950049278
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Barghouthi, I. A.
(Utah State Univ. Logan, UT, United States)
Barakat, A. R.
(Utah State Univ. Logan, UT, United States)
Schunk, R. W.
(Utah State Univ. Logan, UT, United States)
Date Acquired
August 16, 2013
Publication Date
November 1, 1994
Publication Information
Publication: Annales Geophysicae
Volume: 12
Issue: 11-Oct
ISSN: 0992-7689
Subject Category
Geophysics
Accession Number
95A80877
Funding Number(s)
CONTRACT_GRANT: NAG5-1484
CONTRACT_GRANT: NAG5-1546
Distribution Limits
Public
Copyright
Other

Available Downloads

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