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Early time evolution of negative ion clouds and electron density depletions produced during electron attachment chemical release experimentsTwo-dimensional electrostatic particle-in-cell simulations are used to study the early time evolution of electron depletions and negative ion clouds produced during electron attachment chemical releases in the ionosphere. The simulation model considers the evolution in the plane perpendicular to the magnetic field and a three-species plasma that contains electrons, positive ions, and also heavy negative ions that result as a by-product of the electron attachment reaction. The early time evolution (less than the negative ion cyclotron period) of the system shows that a negative charge surplus initially develops outside of the depletion boundary as the heavy negative ions move across the boundary. The electrons are initially restricted from moving into the depletion due to the magnetic field. An inhomogenous electric field develops across the boundary layer due to this charge separation. A highly sheared electron flow velocity develops in the depletion boundary due to E x B and Delta-N x B drifts that result from electron density gradients and this inhomogenous electric field. Structure eventually develops in the depletion boundary layer due to low-frequency electrostatic waves that have growth times shorter than the negative ion cyclotron period. It is proposed that these waves are most likely produced by the electron-ion hybrid instability that results from sufficiently large shears in the electron flow velocity.
Document ID
19950038038
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Scales, W. A.
(Virginia Tech, Blacksburg, VA United States)
Bernhardt, P. A.
(Naval Research Laboratory, Washington, DC United States)
Ganguli, G.
(Naval Research Laboratory, Washington, DC United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1994
Publication Information
Publication: Journal of Geophysical Research
Volume: 99
Issue: A1
ISSN: 0148-0227
Subject Category
Geophysics
Accession Number
95A69637
Funding Number(s)
CONTRACT_GRANT: N00014-92-J-1484
CONTRACT_GRANT: N00014-92-J-1498
Distribution Limits
Public
Copyright
Other

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