Plasma q-profile control in tokamaks using a damping assignment passivity-based approach

Vu, Ngoc Minh Trang; Nouailletas, R.; Lefèvre, Laurent; Felici, F.

doi:10.1016/j.conengprac.2016.05.003

Cited by 11 publications

(22 citation statements)

References 13 publications

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“…Using the first version of the system, with generic controllers and a preliminary actuator manager, RT integrated control of NTMs, β and model-estimated q profiles has been demonstrated on TCV. The details of various β and q profile controllers have been presented in references [23][24][25], and here we only concentrate on the generic NTM controller. As shown in figure 21 and preliminarily presented in reference [26], three EC launchers (L1, L4 and L6) are used to perform the three control tasks.…”

Section: Rt Integrated Control Of Ntms β and Model-estimated Q Profimentioning

confidence: 99%

Control of neoclassical tearing modes and integrated multi-actuator plasma control on TCV

et al. 2019

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The control of 2/1 neoclassical tearing modes (NTMs) with electron cyclotron (EC) waves has been studied both experimentally and numerically on TCV. Dynamic evolutions of NTMs along with time-varying deposition locations of the control beam have been studied in detail. The prevention of NTMs by means of preemptive EC (i.e. the control beam is switched on before the mode onset) has also been explored. A small sinusoidal sweeping with full amplitude of 0.07 (normalized to the minor radius) has been added to the control beam in two of the experiments to facilitate the comparison between NTM stabilization and prevention. It is shown that the prevention of NTMs is more efficient than NTM stabilization in terms of the minimum EC power required. Interpretative simulations with the Modified Rutherford Equation (MRE) have been performed to better quantify various effects, with coefficients well defined by dedicated experiments. Specifically, in order to obtain more insight on the dominant dependencies, a simple ad-hoc analytical model has been proposed to evaluate the time-varying classical stability index ∆ in the test discharges, based on the ∆ -triggered nature of these 2/1 NTMs. This allows simulating well the entire island width evolution with the MRE, starting from zero width and including both NTM stabilization and prevention cases for the first time. The exploration of NTM physics and control has facilitated the development of an NTM controller that is independent of the particular features of TCV and has been included in a generic plasma control system (PCS) framework. Integrated control of 2/1 NTMs, plasma β (the ratio of plasma pressure to magnetic pressure) and model-estimated safety factor q profiles has been demonstrated on TCV.

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Section: Rt Integrated Control Of Ntms β and Model-estimated Q Profimentioning

confidence: 99%

Control of neoclassical tearing modes and integrated multi-actuator plasma control on TCV

et al. 2019

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“…13is indicated in each frame. 5 • 10 19 m −3 and the plasma current varies between 0.6 MA and 1.2 MA depending on the values of the heating and current drive actuators. The simulations were divided into several groups presented on Table 1.…”

Section: Identification Resultsmentioning

confidence: 99%

“…The dynamics of the poloidal magnetic flux profile can be represented by a resistive diffusion, a parabolic equation with spatially distributed rapidly time-varying coefficients. Model-based methods for feedback control of the safety factor profile (also called the q-profile) using Multiple-Input and Multiple-Output (MIMO) finite dimensional systems are developed in [2,3,4,5], and using control algorithms based on infinite dimensional control theory are developed in [6,7,8,9]. The poloidal magnetic flux and the electron temperature are known to be highly coupled [1].…”

Section: Introductionmentioning

confidence: 99%

Multi-experiment state-space identification of coupled magnetic and kinetic parameters in tokamak plasmas

Mavkov

Witrant

Prieur

et al. 2017

Control Engineering Practice

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International audienceThis paper describes an identification technique for control-oriented linear time-invariant models of the coupled dynamics of the electron temperature and the poloidal magnetic flux for advanced operational tokamak scenarios. The actuators consist of two neutral beam injectors, an electron cyclotron current drive and the ohmic coil that provides the loop voltage at the plasma surface. The model is identified using a combination of subspace and output-error methods for state-space multiple-input and multiple-output system identification. This identification is applied on sets of simulated data from the METIS tokamak simulator with parameters typical of the DIII-D tokamak, and the results of the identification are presented

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“…The q changes are rather small owing to the long global current redistribution time for JET discharges at these temperatures (typically ∼ 10s). The values of H 98 are (0.796, 0.7560.755) at t = [1,3,5] respectively.…”

Section: Nbi Input Power Scan Including Core-pedestal Couplingmentioning

confidence: 99%

Real-time-capable prediction of temperature and density profiles in a tokamak using RAPTOR and a first-principle-based transport model

et al. 2018

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The RAPTOR code is a control-oriented core plasma profile simulator with various applications in control design and verification, discharge optimization and realtime plasma simulation. To date, RAPTOR was capable of simulating the evolution of poloidal flux and electron temperature using empirical transport models, and required the user to input assumptions on the other profiles and plasma parameters. We present an extension of the code to simulate the temperature evolution of both ions and electrons, as well as the particle density transport. A proof-of-principle neural-network emulation of the quasilinear gyrokinetic QuaLiKiz transport model is coupled to RAPTOR for the calculation of first-principle-based heat and particle turbulent transport. These extended capabilities are demonstrated in a simulation of a JET discharge. The multi-channel simulation requires ∼ 0.2 second to simulate 1 second of a JET plasma, corresponding to ∼20 energy confinement times, while predicting experimental profiles within the limits of the transport model. The transport model requires no external inputs except for the boundary condition at the top of the H-mode pedestal. This marks the first time that simultaneous, accurate predictions of Te, T i and ne have been obtained using a first-principle-based transport code that can run in faster-than-real-time for present-day tokamaks.

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Plasma q-profile control in tokamaks using a damping assignment passivity-based approach

Cited by 11 publications

References 13 publications

Control of neoclassical tearing modes and integrated multi-actuator plasma control on TCV

Control of neoclassical tearing modes and integrated multi-actuator plasma control on TCV

Multi-experiment state-space identification of coupled magnetic and kinetic parameters in tokamak plasmas

Real-time-capable prediction of temperature and density profiles in a tokamak using RAPTOR and a first-principle-based transport model

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