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Electron temperature control of PMSE
Author(s) -
Rapp Markus,
Lübken FranzJosef
Publication year - 2000
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 - 10.1029/2000gl011922
Subject(s) - electron , electron temperature , thermal diffusivity , diffusion , atomic physics , ion , electric field , mesosphere , wavelength , aerosol , materials science , molecular physics , physics , atmospheric sciences , optics , meteorology , quantum mechanics , stratosphere , thermodynamics
Recently an artificially induced modulation of polar mesosphere summer echos (PMSE) was observed when the electrons at PMSE altitudes were heated by a ground based heating facility [ Chilson et al. , 2000]. The PMSE disappeared within a few seconds when the heater was switched on and reappeared within a few seconds when the heater was switched off again. We explain these observations employing a model of electron diffusion in the environment of positive ions and negatively charged aerosols which takes into account enhanced electron temperatures. If the electron temperature equals the neutral gas temperature, electron diffusion is efficiently inhibited due to the multipolar electric field between the aerosols, positive ions, and electrons. If the electron temperature is enhanced, however, the electron diffusivity is increased which compensates the effect of charged aerosols such that spatial structures in the electron gas at scales as small as the radar half wavelength are efficiently destroyed by diffusion. Furthermore, an enhanced electron temperature increases the aerosol charge which supports the decay of electron disturbance through plasma interference effects. The heating experiment has demonstrated that the reduction of electron diffusivity by charged aerosol particles is the underlying physical mechanism for the existence of PMSE.