TY - JOUR
T1 - Optimal control of the plasma azimuthal velocity profile by feedback E× B actuation in HELCAT
AU - Ilhan, Zeki Okan
AU - Huxley-Cohen, David
AU - Wang, Hexiang
AU - Schuster, Eugenio
AU - Gilmore, Mark
AU - Ware, Andrew
PY - 2014/3
Y1 - 2014/3
N2 - Active control of the flow shear, which is related to the radial derivative of the azimuthal flow, is a key factor in reducing the cross-field turbulence-driven particle transport in a magnetically confined plasma column. 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. In this paper, a model-based feedback controller is proposed to overcome this challenge in helicon-cathode (HELCAT). This linear, dual-source, magnetized-plasma, laboratory device employs concentric ring electrodes to mitigate the turbulent plasma transport by generating a sheared radial electric field and modifying the flow profiles by E×B actuation. A linear-quadratic-integral optimal feedback controller is designed to minimize a weighted combination of the tracking error and the control effort with an ultimate goal of regulating the radial azimuthal velocity profile around a prescribed desired profile even with external disturbances and perturbed initial conditions. Numerical simulations show the effectiveness of the proposed controller in shaping the azimuthal flow profile in HELCAT. The proposed control solution has the potential of being used as a systematic tool for physics-oriented studies in laboratory plasmas such as those achieved in HELCAT.
AB - Active control of the flow shear, which is related to the radial derivative of the azimuthal flow, is a key factor in reducing the cross-field turbulence-driven particle transport in a magnetically confined plasma column. 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. In this paper, a model-based feedback controller is proposed to overcome this challenge in helicon-cathode (HELCAT). This linear, dual-source, magnetized-plasma, laboratory device employs concentric ring electrodes to mitigate the turbulent plasma transport by generating a sheared radial electric field and modifying the flow profiles by E×B actuation. A linear-quadratic-integral optimal feedback controller is designed to minimize a weighted combination of the tracking error and the control effort with an ultimate goal of regulating the radial azimuthal velocity profile around a prescribed desired profile even with external disturbances and perturbed initial conditions. Numerical simulations show the effectiveness of the proposed controller in shaping the azimuthal flow profile in HELCAT. The proposed control solution has the potential of being used as a systematic tool for physics-oriented studies in laboratory plasmas such as those achieved in HELCAT.
KW - Azimuthal velocity profile control
KW - optimal linear-quadratic-integral feedback control
KW - plasma transport control
UR - http://www.scopus.com/inward/record.url?scp=84896492366&partnerID=8YFLogxK
U2 - 10.1109/TPS.2014.2304727
DO - 10.1109/TPS.2014.2304727
M3 - Article
AN - SCOPUS:84896492366
SN - 0093-3813
VL - 42
SP - 469
EP - 476
JO - IEEE Transactions on Plasma Science
JF - IEEE Transactions on Plasma Science
IS - 3
M1 - 6750102
ER -