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Return currents from a single probe in a magnetized plasma
Author(s) -
Weinlich M.,
Carlson A.,
Rohde V.,
Reinmüller K.
Publication year - 1998
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/ctpp.19980380107
Subject(s) - plasma , asdex upgrade , langmuir probe , electrical resistivity and conductivity , plasma parameters , current (fluid) , upgrade , mechanics , physics , electric current , tokamak , power (physics) , nonlinear system , computational physics , atomic physics , plasma diagnostics , materials science , nuclear physics , computer science , quantum mechanics , thermodynamics , operating system
Abstract Measurements with a single Langmuir probe are in principle a simple electrostatic problem. The probe, the plasma, the power supply and the vacuum vessel form a closed electric circuit. If all resistivities except the sheath resistance in front of the probe can be neglected the measured nonlinear I – V characteristic allows for an evaluation of density and temperature of the plasma. For a complete analysis we have at least to discuss the influence of all other possible resistivities and therefore we must know the exact way, where and how the current path inside the plasma is closed. Dedicated measurements for the flush mounted target plate probes at ASDEX Upgrade as well as theoretical models show that the sheath resistance at the return area has to be accounted for whereas the parallel Spitzer resistivity can be neglected under most circumstances.