Electron temperature profiles in RFX-mod
2008 (English)In: Plasma Physics and Controlled Fusion, ISSN 0741-3335, E-ISSN 1361-6587, Vol. 50, no 3, 035013- p.Article in journal (Refereed) Published
Electron temperature profiles have been measured by the main Thomson scattering ( TS) diagnostic on the RFX-mod reversed field pinch experiment in Padova, Italy. The increased accuracy and spatial and temporal resolution permits one to measure in detail the improvements in T-e profiles, obtained with the active saddle coil system, which allows one to obtain core temperature 30% higher and scaling stronger with plasma current, steeper gradients in the core (+30%) and at the edge (+60%). 1D power balance calculations show that the active control of MHD modes largely reduces the values of electron heat diffusivity along the whole plasma radius, with similar to 50% reduction at the edge and similar to 30% in the core. The resulting electron energy confinement time is doubled. Further improvements occur during quasi-single helicity (QSH) states: the new TS allows one to study in detail the hot island that develops in the core. A characterization of the island electron thermal profile is presented, in terms of width, temperature increase, gradients and asymmetry; the effect on density profile is also discussed. A 2D transport code has been applied to calculate the heat diffusivity inside the magnetic island corresponding to the QSH state, also considering the correlation between temperature increase and pressure gradient with the chaos level around the island. Finally, electron energy confinement time during QSH states is compared with that in MH states.
Place, publisher, year, edition, pages
2008. Vol. 50, no 3, 035013- p.
REVERSED-FIELD PINCH, MAGNETIC SELF-ORGANIZATION, THOMSON SCATTERING SYSTEM, ACTIVE MHD CONTROL, CONFINEMENT, TRANSPORT, RESOLUTION, PLASMAS
Fusion, Plasma and Space Physics
IdentifiersURN: urn:nbn:se:kth:diva-33089DOI: 10.1088/0741-3335/50/3/035013ISI: 000254359700013ScopusID: 2-s2.0-43049112758OAI: oai:DiVA.org:kth-33089DiVA: diva2:415378
QC 201507202011-05-062011-04-282015-07-20Bibliographically approved