ALL libraries (COBIB.SI union bibliographic/catalogue database)
  • JET ([sup]3He)-D scenarios relying on RF heating : survey of selected recent experiments
    Eester, D. Van ...
    Recent JET experiments have been devoted to the study of (He-3)-D plasmas involving radio frequency (RF) heating. This paper starts by discussing the RFheating efficiency theoretically expected in ... such plasmas, covering both relevant aspects of wave and of particle dynamics. Then it gives a concise summary of the main conclusions drawn from recent experiments that were eitherfocusing on studying RF heating physics aspects or that were adopting RFheating as a tool to study plasma behavior. Depending on the minority concentration chosen, different physical phenomena are observed. At very low concentration (XšHe-3đ < 1%), energetic tails are formed which trigger MHD activity and result in loss of fast particles. Alfven cascades were observed and gamma ray tomography indirectly shows the impact of sawtooth crashes on the fast particle orbits. Low concentration (XšHe-3đ < 10%) favors minority heating while for XšHe-3đ >> 10% electron mode conversion damping becomes dominant. Evidence for the Fuchs et al standing wave effect (Fuchs et al 1995 Phys. Plasmas 2 1637-47) on the absorption is presented. RF induced deuterium tails were observed in mode conversion experiments with large XšHe-3đ (approximate to 18%). As tentative modeling shows, the formation of these tails can be explained as a consequence of wave power absorption by neutral beam particles that efficiently interact with the waves well away from the cold D cyclotron resonance position as a result of their substantial Doppler shift. As both ion and electron RF power deposition profiles in (He-3)-D plasmas are fairly narrow-giving rise to localized heat sources-the RF heatingmethod is an ideal tool for performing transport studies. Various of the experiments discussed here were done in plasmas with internal transport barriers (ITBs). ITBs are identified as regions with locally reduced diffusivity, where poloidal spinning up of the plasma is observed. The presentknow-how on the role of RF heating for impurity transport is also briefly summarized.
    Source: Plasma physics and controlled fusion. - ISSN 0741-3335 (Iss. 4, Vol. 51, 2009, 044007-1-044007-32)
    Type of material - article, component part
    Publish date - 2009
    Language - english
    COBISS.SI-ID - 24718119

source: Plasma physics and controlled fusion. - ISSN 0741-3335 (Iss. 4, Vol. 51, 2009, 044007-1-044007-32)
loading ...
loading ...
loading ...

Shelf entry