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Polarization electric field and Farley-Buneman instability during a precipitation event.

del Pozo, C. F. (1994) Polarization electric field and Farley-Buneman instability during a precipitation event. Journal of Atmospheric and Terrestrial Physics, 56 (4). pp. 509-523.

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Abstract

An anomalous polarization electric field may be set-up in the lower auroral E-region in response to an electron precipitation event during unstable electrojet conditions. For instance, observations during post-midnight to early morning hours on 06–07 June 1990, using the EISCAT radar facility in Scandinavia, show that the in-situ dynamics of the E-region ionization may be radically affected by the presence of the Farley-Buneman instability. In this case, the measured ion drifts at 105 km height are exceptionally strong and comparable in magnitude with the E × B-drift in the F-region, mapped along the same magnetic fieldline. In this paper we present a model to explain the main features of these observations. We assume a simple relaxation model for the E-region ionization generated by an instantaneous electron precipitation event during diffuse aurora conditions and in the presence of the Farley-Buneman instability. In these conditions and for times smaller than the ionization lifetime (tens of seconds to a few minutes), the induced polarization electric field to restore charge quasi-neutrality may radically increase the ion drift velocity, and effectively decouple the ion motion from the dynamics of the neutral atmosphere.

Item Type: Article
Journal or Publication Title: Journal of Atmospheric and Terrestrial Physics
Uncontrolled Keywords: Polar ionosphere ; Ionospheric E region ; Electric field ; Polarization ; Buneman Farley instability ; Particle precipitation ; Drift velocity
Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
Departments: Faculty of Science and Technology > Lancaster Environment Centre
ID Code: 22672
Deposited By: ep_ss_importer
Deposited On: 20 Jan 2009 12:56
Refereed?: No
Published?: Published
Last Modified: 26 Jul 2012 16:04
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/22672

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