Optimal closed-loop control of the azimuthal velocity profile by E×B actuation in HELCAT

Zeki Okan Ilhan, David Huxley-Cohen, Hexiang Wang, Eugenio Schuster, Mark Gilmore, Andrew Ware

    Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

    Abstract

    The cross-field turbulence-driven particle transport in magnetically confined plasmas can be reduced by adequately shaping the flow profiles. HELCAT (HELicon-CAThode), a linear magnetized plasma device, uses concentric ring electrodes to modify the flow profiles by E×B actuation. As a result, turbulent particle and heat transport can be mitigated by generating a sheared radial electric field through the varying ring voltages. Active control of the turbulent fluctuations, including the associated cross-field particle transport, via manipulation of flow profiles is investigated in this work. Once a desired radial azimuthal velocity profile, and its associated level of turbulent fluctuations, are identified, the challenge of systematically achieving and sustaining it still remains. A model-based feedback controller is proposed to achieve this goal even in the presence of external disturbances, model uncertainties and perturbed initial conditions. A linear-quadratic-integral (LQI) optimal controller is designed to minimize a weighted combination of the tracking error and the control effort. Numerical simulations show the effectiveness of the proposed controller to regulate the radial azimuthal velocity profile around a prescribed desired profile. The proposed control solution has the potential of being used as a systematic tool to elucidate the physics of laboratory plasmas such as those achieved in HELCAT.

    Original languageEnglish
    Title of host publication2013 IEEE 25th Symposium on Fusion Engineering, SOFE 2013
    DOIs
    StatePublished - 2013
    Event2013 IEEE 25th Symposium on Fusion Engineering, SOFE 2013 - San Francisco, CA, United States
    Duration: Jun 10 2013Jun 14 2013

    Publication series

    Name2013 IEEE 25th Symposium on Fusion Engineering, SOFE 2013

    Conference

    Conference2013 IEEE 25th Symposium on Fusion Engineering, SOFE 2013
    Country/TerritoryUnited States
    CitySan Francisco, CA
    Period06/10/1306/14/13

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