Hydrogen plasmas with ICRF inverted minority and mode conversion heating regimes in the JET tokamak
2006 (English)In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 46, no 7, S550-S563 p.Article in journal (Refereed) Published
During the initial operation of the International Thermonuclear Experimental Reactor (ITER), it is envisaged that activation will be minimized by using hydrogen (H) plasmas where the reference ion cyclotron resonance frequency (ICRF) heating scenarios rely on minority species such as helium (He-3) or deuterium (D). This paper firstly describes experiments dedicated to the study of He-3 heating in H plasmas with a sequence of discharges in which 5 MW of ICRF power was reliably coupled and the He-3 concentration, controlled in real-time, was varied from below 1% up to 10%. The minority heating (MH) regime was observed at low concentrations (up to 2%). Energetic tails in the He-3 ion distributions were observed with effective temperatures up to 300 keV and bulk electron temperatures up to 6 keV. At around 2%, a sudden transition was reproducibly observed to the mode conversion regime, in which the ICRF fast wave couples to short wavelength modes, leading to efficient direct electron heating and bulk electron temperatures up to 8 keV. Secondly, experiments performed to study D minority ion heating in H plasmas are presented. This MH scheme proved much more difficult since modest quantities of carbon
Place, publisher, year, edition, pages
2006. Vol. 46, no 7, S550-S563 p.
toroidal plasmas, ion-cyclotron, waves, injection, transport, profile
IdentifiersURN: urn:nbn:se:kth:diva-15889DOI: 10.1088/0029-5515/46/7/S14ISI: 000239478900015OAI: oai:DiVA.org:kth-15889DiVA: diva2:333931
QC 201005252010-08-052010-08-05Bibliographically approved