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Laboratory model of a tethered balloon – electron beam current system
Author(s) -
Stenzel R. L.,
Urrutia J. M.
Publication year - 1986
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/gl013i008p00797
Subject(s) - current (fluid) , plasma , cathode ray , physics , electron , magnetic field , beam (structure) , saturation current , electrode , atomic physics , space charge , voltage , optics , quantum mechanics , thermodynamics
In a large laboratory magneto‐plasma, the current flow is investigated between a field‐aligned electron beam and an electrode collecting return current on a separate flux tube. The space‐time evolution of the current system shows spiraling currents penetrating alongB → onear electron thermal speeds (v ≲ v the » v Alfvén ). The electron beam propagates faster than the current, hence its front is current neutralized. Anomalous cross‐field currents shunt the field‐aligned currents, preventing the formation of a long current loop. Plasma expulsion by the return‐current collecting electrode disrupts the large initial currents which are one order of magnitude above the electron saturation current. The plasma dynamics causes repeated current bursts and periodic charging of the beam/electrode with respect to the plasma potential.