Toroidal rotation in RF heated JET plasmas
2009 (English)In: Plasma Physics and Controlled Fusion, ISSN 0741-3335, E-ISSN 1361-6587, Vol. 51, no 4Article in journal (Refereed) Published
Observations of bulk plasma rotation in radio frequency (RF) heated JET discharges are reported. This study is concentrated on RF heated L-mode plasmas. In particular, the toroidal rotation profiles in plasmas heated by ion cyclotron resonance frequency (ICRF) waves and lower hybrid (LH) waves have been analysed. It is the first time that rotation profiles in JET plasmas with LH waves have been measured in dedicated discharges. It is found that the toroidal plasma rotation in the outer region of the plasmas is in the co-current direction irrespective of the heating scenario. An interesting feature is that the toroidal rotation profile appears to be hollow in many discharges at low plasma current, but a low current in itself does not seem to be a sufficient condition for finding such profiles. Fast ion transport and finite orbit width effects are mechanisms that could explain hollow rotation profiles. This possibility has been investigated by numerical simulations of the torque on the bulk plasma due to fast ICRF accelerated ions. The obtained torque is used in a transport equation for the toroidal momentum density to estimate the effect on the thermal bulk plasma rotation profile.
Place, publisher, year, edition, pages
2009. Vol. 51, no 4
IdentifiersURN: urn:nbn:se:kth:diva-18315DOI: 10.1088/0741-3335/51/4/044008ISI: 000264708500009ScopusID: 2-s2.0-67649700827OAI: oai:DiVA.org:kth-18315DiVA: diva2:336361
QC 201005252010-08-052010-08-052012-03-20Bibliographically approved