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Space-charge sheath with ions accelerated into the plasma
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Authors
Advisor(s)
Abstract(s)
The conventional model of near-cathode space-charge sheath with ions entering the sheath
from the quasi-neutral plasma may not be applicable to discharges burning in cathode vapour,
e.g. vacuum arcs, where ionization of emitted atoms may occur inside the sheath with some of
the produced ions returning to the cathode and others moving into the plasma. In this
connection, a simple model is considered of a sheath formed by electrons and positive ions
injected into the sheath with a very low velocity and moving from the sheath into the plasma.
It is shown that such a sheath is possible provided that the sheath voltage is equal to or exceeds
approximately 1.256kTe/e. This limitation is due to the space charge in the sheath and is in
this sense analogous to the limitation of ion current in a vacuum diode expressed by the
Child–Langmuir law. The ions leave the sheath and enter the plasma with a velocity equal to
or exceeding approximately 1.585uB.
Description
Keywords
Space-charge sheath Ions Plasma . Faculdade de Ciências Extas e da Engenharia
Citation
Benilov, M. S. (2010). Space-charge sheath with ions accelerated into the plasma. Journal of Physics D: Applied Physics, 43(17), 175203. DOI: 10.1088/0022-3727/43/17/175203
Publisher
IOP Publishing