Mitigation of Alfvén activity in a tokamak by externally applied static 3d fields

A. Bortolon, W. W. Heidbrink, G. J. Kramer, J. K. Park, E. D. Fredrickson, J. D. Lore, M. Podestà

    Research output: Contribution to journalArticlepeer-review

    48 Scopus citations

    Abstract

    The application of static magnetic field perturbations to a tokamak plasma is observed to alter the dynamics of high-frequency bursting Alfvén modes that are driven unstable by energetic ions. In response to perturbations with an amplitude of δB/B∼0.01 at the plasma boundary, the mode amplitude is reduced, the bursting frequency is increased, and the frequency chirp is smaller. For modes of weaker bursting character, the magnetic perturbation induces a temporary transition to a saturated continuous mode. Calculations of the perturbed distribution function indicate that the 3D perturbation affects the orbits of fast ions that resonate with the bursting modes. The experimental evidence represents an important demonstration of the possibility of controlling fast-ion instabilities through "phase-space engineering" of the fast-ion distribution function, by means of externally applied perturbation fields.

    Original languageEnglish
    Article number265008
    JournalPhysical Review Letters
    Volume110
    Issue number26
    DOIs
    StatePublished - Jun 28 2013

    Fingerprint

    Dive into the research topics of 'Mitigation of Alfvén activity in a tokamak by externally applied static 3d fields'. Together they form a unique fingerprint.

    Cite this