000176059 001__ 176059
000176059 005__ 20190228220043.0
000176059 0247_ $$2doi$$a10.1088/0029-5515/52/2/023019
000176059 02470 $$2ISI$$a000300794500019
000176059 037__ $$aARTICLE
000176059 245__ $$aDevelopment and validation of a tokamak skin effect transformer model
000176059 269__ $$a2012
000176059 260__ $$c2012
000176059 336__ $$aJournal Articles
000176059 520__ $$aA lumped parameter, state space model for a tokamak transformer including the slow flux penetration in the plasma (skin effect transformer model) is presented. The model does not require detailed or explicit information about plasma profiles or geometry. Instead, this information is lumped in system variables, parameters and inputs. The model has an exact mathematical structure built from energy and flux conservation theorems, predicting the evolution and non-linear interaction of plasma current and internal inductance as functions of the primary coil currents, plasma resistance, non-inductive current drive and the loop voltage at a specific location inside the plasma (equilibrium loop voltage). Loop voltage profile in the plasma is substituted by a three-point discretization, and ordinary differential equations are used to predict the equilibrium loop voltage as a function of the boundary and resistive loop voltages. This provides a model for equilibrium loop voltage evolution, which is reminiscent of the skin effect. The order and parameters of this differential equation are determined empirically using system identification techniques. Fast plasma current modulation experiments with random binary signals have been conducted in the TCV tokamak to generate the required data for the analysis. Plasma current was modulated under ohmic conditions between 200 and 300 kA with 30 ms rise time, several times faster than its time constant L/R approximate to 200 ms. A second-order linear differential equation for equilibrium loop voltage is sufficient to describe the plasma current and internal inductance modulation with 70% and 38% fit parameters, respectively. The model explains the most salient features of the plasma current transients, such as the inverse correlation between plasma current ramp rates and internal inductance changes, without requiring detailed or explicit information about resistivity profiles. This proves that a lumped parameter modelling approach can be used to predict the time evolution of bulk plasma properties such as plasma inductance or current with reasonable accuracy; at least under ohmic conditions without external heating and current drive sources.
000176059 6531_ $$aPlasma Equilibrium Response
000176059 6531_ $$aOutput Parametric Models
000176059 6531_ $$aNon-Linear Systems
000176059 6531_ $$aExternal Inductance
000176059 6531_ $$aMagnetic Control
000176059 6531_ $$aCurrent Drive
000176059 6531_ $$aTcv
000176059 6531_ $$aReactor
000176059 6531_ $$aCode
000176059 6531_ $$aSimulation
000176059 700__ $$aRomero, J. A.
000176059 700__ $$aMoret, J.-M.
000176059 700__ $$aCoda, S.
000176059 700__ $$aFelici, F.
000176059 700__ $$aGarrido, I.
000176059 773__ $$j52$$tNuclear Fusion$$q023019
000176059 909C0 $$pCRPP
000176059 909C0 $$0252028$$pSPC
000176059 909CO $$pSB$$particle$$ooai:infoscience.tind.io:176059
000176059 909C0 $$xU12272$$xU12268$$xU10558$$xU10635$$xU12266$$xU10636$$xU10137$$xU12270$$xU10557$$xU12273$$xU10559$$xU12271$$xU12269$$xU12267$$xU10136
000176059 917Z8 $$x112823
000176059 917Z8 $$x112823
000176059 917Z8 $$x105317
000176059 937__ $$aEPFL-ARTICLE-176059
000176059 973__ $$rREVIEWED$$sPUBLISHED$$aEPFL
000176059 980__ $$aARTICLE