Observation of warm, higher energy electrons transiting a double layer in a helicon plasma

Journal Article · Sun Mar 15 00:00:00 EDT 2015 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4916051· OSTI ID:22408274

Sung, Yung-Ta; Li, Yan; Scharer, John E. ^[1]

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1. Department of Electrical and Computer Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706 (United States)

Measurements of an inductive RF helicon argon plasma double layer with two temperature electron distributions including a fast (>80 eV) tail are observed at 0.17 mTorr Ar pressure. The fast, untrapped electrons observed downstream of the double layer have a higher temperature (13 eV) than the trapped (T{sub e} = 4 eV) electrons. The reduction of plasma potential and density observed in the double layer region would require an upstream temperature ten times the measured 4 eV if occurring via Boltzmann ambipolar expansion. The experimental observation in Madison helicon experiment indicates that fast electrons with substantial density fractions can be created at low helicon operating pressures.

• OSTI ID: 22408274
• Journal Information: Physics of Plasmas, Vol. 22, Issue 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ARGON
BOLTZMANN EQUATION
ELECTRON TEMPERATURE
EV RANGE
PLASMA
PLASMA DENSITY
PLASMA POTENTIAL
RADIOWAVE RADIATION
TAIL ELECTRONS
TRAPPED ELECTRONS