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Author(s):
K. Sato and F. Miyawaki
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Title:
Formation of Presheath and Current-Free Double Layer in a Two-Electron-Temperture Plasma
Date of publication:
Feb. 1992
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Key words:
presheath, current-free double layer, two-temperature-electron plasma, potential formation, energetic electrons, plasma equation
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Abstract:
Development of the steady-state potential in a two-temperature-electron plasma in contact with the wall is investigated analytically. It is shown that if the hot- to cold electron temperature ratio is greater than ten, the potential drop in the presheath, which is allowed to have either a small value characterized by the cold electrons or a large value by the hot electrons, discontinuously changes at a critical value for the hot- to total electron density ratio. It is also found that the monotonically decreasing potential structure which consists of the first presheath, a current-free double layer, the second presheath, and the sheath can be steadily formed in a lower range of the hot- to total electron density ratio around the critical value. The current-free double layer is set up due to existence of the two electron species and cold ions generated by ionization so as to connect two presheath potentials at different levels.
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