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Sondenmessungen in einem durch Kontaktionisation erzeugten Cäsium‐Plasma
Author(s) -
Fuchs G.,
Walcher W.,
Wiesemann K.
Publication year - 1970
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/andp.19704790510
Subject(s) - plasma , common emitter , atomic physics , torr , materials science , ionization , electron , electron temperature , ion , caesium , physics , optoelectronics , thermodynamics , quantum mechanics , nuclear physics
Using a hot wire (emitter) in the axis of a cylindrical glass vessel containing cesium vapour a plasma was formed by contact ionization. The plasma diffuses to the walls where it recombines. Plasma density, electron temperature (respectively the energy distribution function of the electrons), and the space potential were measured by probes in different distances from the emitter. Perturbations of the plasma by the current in the directly heated emitter are eliminated by using a pulsed current and a sampling method for the probe measurements. At vapour pressures exceeding 10 −3 Torr the plasma follows the equilibrium theory. At low pressures when an ion sheath at the emitter is present nonmaxwellian electron distribution functions occur. The perturbations of the plasma by the probe are thoroughly discussed.