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The interaction between the thermosphere and ionosphere at high latitudes

The interaction between the thermosphere and ionosphere at high latitudes
The interaction between the thermosphere and ionosphere at high latitudes
A study has been made of the interaction between the thermosphere and the ionosphere at high latitudes, with particular attention to the value of the 0+-0 collision parameter. The European Incoherent SCATter facility
(EISCAT) based at Troms0 was used to make tristatic
measurements of plasma parameters at F region altitudes
while simultaneous independent measurements of the
neutral wind were made by a Fabry-Perot Interferometer
(FPI). The radar data were used to derive values of the
meridional neutral wind. The accuracy of this technique
at high latitudes is reduced by the dynamic nature of the
auroral ionosphere and the presence of significant
vertical winds. The derived winds were compared with the
meridional winds measured by the FPI. For each night, the
value of the 0*-0 collision parameter was found which
produced the best agreement between the two data sets.
The precision of the collision frequency obtained in this
way depends on the accuracy of the data. The statistical
method was critically examined in an attempt to account
for the variability in the data sets. The results
indicate that the most probable value of the 0+-0
collision parameter is a factor of between 1.2 and 1.7
greater than Banks' theoretical value (Banks, 1966).
The contribution of ion drag to the acceleration of the
neutral air was also considered. During times of enhanced
ion drift, ion drag dominates all other forces acting on
the neutral air. A method for determining the neutral ion
collision frequency during such an event is described. It
was not possible to calculate the neutral ion collision frequency for the two examples in this thesis due to limitations in the radar data.
University of Southampton
Davis, Christopher
8c8d7743-dbbe-498f-a0da-7377102b01fc
Davis, Christopher
8c8d7743-dbbe-498f-a0da-7377102b01fc
Rishbeth, Henry
472ad744-0f44-4325-9930-c2c06cdbf4a3

Davis, Christopher (1993) The interaction between the thermosphere and ionosphere at high latitudes. University of Southampton, Doctoral Thesis, 209pp.

Record type: Thesis (Doctoral)

Abstract

A study has been made of the interaction between the thermosphere and the ionosphere at high latitudes, with particular attention to the value of the 0+-0 collision parameter. The European Incoherent SCATter facility
(EISCAT) based at Troms0 was used to make tristatic
measurements of plasma parameters at F region altitudes
while simultaneous independent measurements of the
neutral wind were made by a Fabry-Perot Interferometer
(FPI). The radar data were used to derive values of the
meridional neutral wind. The accuracy of this technique
at high latitudes is reduced by the dynamic nature of the
auroral ionosphere and the presence of significant
vertical winds. The derived winds were compared with the
meridional winds measured by the FPI. For each night, the
value of the 0*-0 collision parameter was found which
produced the best agreement between the two data sets.
The precision of the collision frequency obtained in this
way depends on the accuracy of the data. The statistical
method was critically examined in an attempt to account
for the variability in the data sets. The results
indicate that the most probable value of the 0+-0
collision parameter is a factor of between 1.2 and 1.7
greater than Banks' theoretical value (Banks, 1966).
The contribution of ion drag to the acceleration of the
neutral air was also considered. During times of enhanced
ion drift, ion drag dominates all other forces acting on
the neutral air. A method for determining the neutral ion
collision frequency during such an event is described. It
was not possible to calculate the neutral ion collision frequency for the two examples in this thesis due to limitations in the radar data.

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Published date: 1 April 1993

Identifiers

Local EPrints ID: 437607
URI: http://eprints.soton.ac.uk/id/eprint/437607
PURE UUID: 596bdec1-0218-4467-b89e-3f078fed03b5

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Date deposited: 06 Feb 2020 17:32
Last modified: 06 Feb 2020 17:32

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Contributors

Author: Christopher Davis
Thesis advisor: Henry Rishbeth

University divisions

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