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Record 23 of 1859
Electron acceleration in stochastic double layers
Author and Affiliation:
Lotko, William(Dartmouth Coll., Hanover, NH, United States)
Abstract: Transversely localized double layers evolve randomly in turbulent regions of strongly magnetized plasma carrying current along the magnetic field. Results from numerical simulations and spacecraft observations in the auroral plasma indicate that the parallel electric field in such regions is microscopically intermittent or stochastic. The implications of stochastic double layer fields on electron acceleration will be discussed in terms of a statistical process involving ensemble averages over test particle motion. A Fokker-Planck equation can be derived for the electron phase space density, which depends on the mean and rms amplitudes of the double layers, the mean double layer density, and the initial electron velocity distribution. It is shown that the resulting electron acceleration is very sensitive to the ratio of the initial electron energy to the rms double layer amplitude. When this ratio is large, the acceleration process differs little from that expected in a dc electric field. When it is small, stochastic heating competes with directed acceleration. Evidence for both cases can be found in the auroral ionosphere in association with so-called inverted-V precipitation and collimated edge precipitation.
Publication Date: May 01, 1987
Document ID:
19870013891
(Acquired Nov 04, 1995)
Accession Number: 87N23324
Subject Category: PLASMA PHYSICS
Coverage: Abstract Only
Document Type: Conference Paper
Publication Information: NASA. Marshall Space Flight Center Double Layers in Astrophysics; p 209
Publisher Information: United States
Financial Sponsor: NASA; United States
Organization Source: Dartmouth Coll.; Hanover, NH, United States
Description: 1p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: AURORAS; ELECTRIC CURRENT; ELECTRIC FIELDS; ELECTRON ACCELERATION; MATHEMATICAL MODELS; PLASMA LAYERS; PLASMAS (PHYSICS); STOCHASTIC PROCESSES; ELECTRON ENERGY; FOKKER-PLANCK EQUATION; MAGNETIC FIELDS; PHASE-SPACE INTEGRAL; VELOCITY DISTRIBUTION
Imprint And Other Notes: In NASA. Marshall Space Flight Center Double Layers in Astrophysics p 209 (SEE N87-23313 16-88)
Availability Source: Other Sources
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