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Influence of Plasma Resistance and Fluctuation on Probe Characteristics in Detached Recombining Plasmas
Author(s) -
Ohno N.,
Tanaka N.,
Ezumi N.,
Nishijima D.,
Takamura S.
Publication year - 2001
Publication title -
contributions to plasma physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.531
H-Index - 47
eISSN - 1521-3986
pISSN - 0863-1042
DOI - 10.1002/1521-3986(200109)41:5<473::aid-ctpp473>3.0.co;2-8
Subject(s) - langmuir probe , plasma , divertor , atomic physics , electron temperature , ion , plasma parameters , plasma diagnostics , materials science , electron , torr , electron density , physics , tokamak , nuclear physics , quantum mechanics , thermodynamics
In order to find the causes of the strong anomaly of current‐voltage characteristics of Langmuir probe observed in detached recombining plasmas in a linear divertor plasma simulator, NAGDIS‐II, we have investigated plasma resistance along a magnetic field and potential fluctuations in the detached recombining plasmas. Simple calculation on the ratio between the plasma length, at which plasma resistance and resistance of ion sheath formed around a probe tip become equal, and an electron collection length indicates that the evaluation of electron temperature T e becomes inaccurate at T e of less than 0.6 eV when plasma density and neutral pressure are 1.0 × 10 18 m —3 and 10 mtorr, respectively. The potential fluctuation in detached recombining plasmas was found to be so large compared to T e / e , which can also modify the probe characteristics.