Stability of JET discharges with zero core current density

B.C. Stratton, J. Breslau, R. Budny, S. Jardin, N.C. Hawkes, T. Hender, G. Huysmans, Tuomas Tala, JET-EFDA contributors

    Research output: Contribution to conferenceConference articleScientificpeer-review


    Injection of lower hybrid heating and current drive into the current ramp-up phase of JET discharges can produce extremely reversed q-profiles characterized by a core region (r/a less than 0.2) of zero current density (within Motional Stark Effect diagnostic measurement errors) and q greater than 1 everywhere [N. C. Hawkes, et al., Phys. Rev. Lett. (accepted July 2001)]. Electron temperature measurements show sawtooth-like collapses and the presence of an internal transport barrier. The core current density does not appear to go negative, although TSC/LSC code modeling indicates that the drive for this is present. A 2-D, two fluid simulation predicts that discharges with negative core current would be unstable to n=0, m=1 modes. The possibility that these modes redistribute the core current to prevent it from becoming negative is examined.
    Original languageEnglish
    Number of pages6
    Publication statusPublished - 2001
    MoE publication typeNot Eligible
    Event43rd Annual Meeting of the APS Division of Plasma Physics - Long Beach, United States
    Duration: 29 Oct 20012 Nov 2001


    Conference43rd Annual Meeting of the APS Division of Plasma Physics
    Country/TerritoryUnited States
    CityLong Beach


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