Estimation of Angular Momentum Transport Coefficients via Extended Kalman Filtering Theory
C. Xu, E. Schuster
Division of Plasma Physics (DPP) Annual Meeting of the American Physical Society (APS)
Atlanta, Georgia, November 2-6, 2009
Abstract
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The accuracy of first-principles predictive models for the evolution
of plasma profiles is sometimes limited by the lack of understanding
of the plasma transport phenomena. In this work we use the extended
Kalman filtering theory to provide real-time estimates of poorly known
or totally unknown angular momentum transport coefficients. These
estimates are based solely on input-output diagnostic data and limited
understanding of the transport physics. We first assume that the
plasma dynamics can be governed by a tractable model obtained by first
principles but the transport coefficients are considered unknown and
to-be-estimated. The partial-differential-equation model is
discretized both in space and time to obtain a finite-dimensional
discrete-time state-space representation. The system states and
to-be-estimated coefficients are then combined into an augmented state
vector. The resulting nonlinear state-space model is used for the
design of an extended Kalman filter that provides real-time
estimations not only of the system states but also of the unknown
transport coefficients.