Interpretation of measurements of ICRF-heated minority proton distributions in JET
In the Joint European Torus (JET) tokamak, the perpendicular velocity distribution function of minority protons in the MeV energy range heated by waves in the ion cyclotron range of frequencies (ICRF) is inferred from neutral particle analyser (NPA) measurements of the emitted hydrogen flux, integrated along a vertical line-of-sight through the plasma centre. In particular, the best-fit perpendicular tail temperature of the inferred distribution can be determined with good accuracy. In this paper a relation is established between this measured quantity and the perpendicular tail temperature of the heated protons at the position of maximum ICRF power deposition. When this model is applied to NPA measurements from a JET pulse with varying levels of applied ICRF power it is found that the scaling of the latter quantity with the applied ICRF power in the 2 MW to 10 MW range is almost exactly linear, as expected from the widely used Stix model. The successful measurement of ICRF-heated proton distributions in the high energy range gives confidence that the NPA instrumentation, and the interpretation techniques described here, could provide valuable data on the behaviour of fusion products in forthcoming deuterium-tritium experiments in JET.
Bibliographic Reference: Report: JET-P(96)50 EN (1996) 12pp.
Availability: Available from the Publications Officer, JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (GB)
Record Number: 199710057 / Last updated on: 1997-02-26
Original language: en
Available languages: en