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:
Journal Article
Journal or Publication Title:
Journal of Atmospheric and Terrestrial Physics
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/2300/2300
Subjects:
?? polar ionosphereionospheric e regionelectric fieldpolarizationbuneman farley instabilityparticle precipitationdrift velocitygeneral environmental sciencegeneral earth and planetary sciencesenvironmental science(all)earth and planetary sciences(all)ge envi ??
ID Code:
22672
Deposited By:
Deposited On:
20 Jan 2009 12:56
Refereed?:
No
Published?:
Published
Last Modified:
16 Jul 2024 08:24