Optimal Azimuthal Velocity Profile Control by ExB Actuation in HELCAT
Z. Ilhan, E. Schuster, S. Xie, M. Gilmore and A. Ware
Division of Plasma Physics (DPP) Annual Meeting of the American Physical Society (APS)
Salt Lake City, Utah, USA, November 14-18, 2011
Abstract
|
|
Turbulence, and turbulence-driven transport are ubiquitous in
magnetically confined plasmas, where there is an intimate relationship
between turbulence, transport, destabilizing mechanisms like gradients
and currents, and stabilizing mechanisms like shear. We investigate
active control of fluctuations via manipulation of flow profiles in a
magnetized laboratory plasma device (HELCAT). Measurements of the
azimuthal velocity are assumed available at several radial points
within the plasma and E×B flow profiles are controlled via biased ring
electrodes. An optimal control algorithm is designed to regulate the
radial azimuthal velocity profile around a prescribed desired profile.
The effectiveness of the controller and the effect of the shape of the
radial azimuthal velocity profile on RMS fluctuations are analyzed via
numerical simulations.