Determination of T(e) from a Langmuir probe in a magnetic field by directly measuring the probe's sheath drop using a pin-plate probeFunded under: EAEC-FUSION 12C
In principle, it is not possible to interpret a Langmuir probe in a strong magnetic field since the modelling of non-ambipolar cross-field transport is uncertain. In some circumstances the portion of the probe I-V characteristic below floating potential may not be contaminated by magnetic field effects, and it can be possible to extract n(e) and T(e) from such data; unfortunately, it is not known with any certainty when this situation holds. By using a special probe with a small collecting element (Pin) just in front of the principal collecting element (Plate) it is possible to correct for the influence of the magnetic field, and to use simple single-probe theory to extract n(e) and T(e). The uncertain influence of the non-ambipolar cross-field transport is entirely characteristic above floating potential; thus, if the electron distribution is non-Maxwellian, that can be measured.
Bibliographic Reference: Report: JET-P(95)21 EN (1995) 11 pp.
Availability: Available from the Publications Officer, JET Joint Undertaking, Abingdon, Oxon. OX14 3EA (GB)
Record Number: 199511445 / Last updated on: 1995-11-03
Original language: en
Available languages: en