Spatially resolved measurements of the electron energy distribution function in a radially inhomogeneous dc plasma column
- Ernst-Moritz-Arndt-Universitaet, Greifswald (Germany)
For a satisfactory description of the radially inhomogeneous plasma of an electric discharge in a cylindrical tube we need information about the influence of the spatial inhomogeneity on the electron energy distribution function (EEDF). Different methods have been developed to solve this problem. The general treatment of this task is based on the solution of the spatially inhomogeneous BOLTZMANN equation. At sufficiently low gas pressure, so that the energy relaxation length {lambda}{sub {epsilon}} is much larger than the radial dimension of the discharge tube, the problem can be simplified. The solution of the BOLTZMANN equation depends under this condition ({lambda}{sub {epsilon}} >> r{sub 0}) only on the total energy {epsilon} = U - u{sub s}(r) (e{sub 0}U = m{sub e}v{sup 2}/2: kinetic energy; e{sub 0}u{sub s}(r): potential energy). This solution is the so called {open_quotes}nonlocal approach{close_quotes}. In this paper the radial dependence of the EEDF has been investigated experimentally by means of LANGMUIR probe measurements. The investigations were carried out in the positive column of a dc neon discharge at low pressure and low current conditions (p{sub 0} = 100 Pa, i = 17 mA, and a diameter of the discharge tube 2r{sub 0} = 34 mm).
- OSTI ID:
- 212854
- Report Number(s):
- CONF-950749--
- Country of Publication:
- United States
- Language:
- English
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