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Wind‐shear‐driven, closed‐current dynamos in midlatitude sporadic E
Author(s) -
Cosgrove Russell B.,
Tsunoda Roland T.
Publication year - 2002
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2001gl013697
Subject(s) - dynamo , middle latitudes , sporadic e propagation , physics , geophysics , wind shear , geology , electric field , current (fluid) , mechanics , atmospheric sciences , ionosphere , meteorology , magnetic field , wind speed , quantum mechanics , thermodynamics
Rocket and radar experiments have found anomalously large electric fields associated with midlatitude sporadic E ( E s ). In Cosgrove and Tsunoda [2001], a neutral wind source mechanism for the electric fields was proposed, by way of a simple model involving two idealized E s patch dynamos closing current with one another. Below, we show that this source mechanism can operate in generic distortions or fragmentations of an E s layer. The result is a closed‐current dynamo phenomenon that occurs whenever a E s layer is distorted against a wind shear background. Either modulation of the E s layer altitude by a gravity wave, or Kelvin‐Helmholtz billows, could produce large electric fields.