Simulation of EAST vertical displacement events by tokamak simulation code

Qiu, Qinglai; Xiao, Bingjia; Guo, Youming; Liu, Lei; Xing, Zhe; Humphreys, D.A.

doi:10.1088/0029-5515/56/10/106029

Cited by 16 publications

(18 citation statements)

References 25 publications

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“…The standard G-S function is used to iterate the poloidal flux Ψ until the convergence criterion is achieved. [6] After the initial equilibrium, all feedback control systems including plasma radial and vertical position control and plasma current control are shut down. A small current pulse is used to trigger the VDE.…”

Section: Model Comparisonmentioning

confidence: 99%

“…The TSC [1] and TokSys [2] are two widely used 2D simulation codes. They have been successfully used on several tokamaks in reproducing experimental VDE shots and/or designing vertical control systems, such as PBX, [1] DIII-D, [2,3] TFTR, [4] JT-60U, [5] EAST [6][7][8] and ITER. [9] The TSC is a full non-linear free boundary simulation code that accurately models the transport time-scale evolution of an axisymmetric plasma, including the plasma interactions with the passive and active feedback systems.…”

Section: Introductionmentioning

confidence: 99%

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Comparison benchmark between tokamak simulation code and TokSys for Chinese Fusion Engineering Test Reactor vertical displacement control design

et al. 2017

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Vertical displacement event (VDE) is a big challenge to the existing tokamak equipment and that being designed. As a Chinese next-step tokamak, the Chinese Fusion Engineering Test Reactor (CFETR) has to pay attention to the VDE study with full-fledged numerical codes during its conceptual design. The tokamak simulation code (TSC) is a free boundary time-dependent axisymmetric tokamak simulation code developed in PPPL, which advances the MHD equations describing the evolution of the plasma in a rectangular domain. The electromagnetic interactions between the surrounding conductor circuits and the plasma are solved self-consistently. The TokSys code is a generic modeling and simulation environment developed in GA. Its RZIP model treats the plasma as a fixed spatial distribution of currents which couple with the surrounding conductors through circuit equations. Both codes have been individually used for the VDE study on many tokamak devices, such as JT-60U, EAST, NSTX, DIII-D, and ITER. Considering the model differences, benchmark work is needed to answer whether they reproduce each other's results correctly. In this paper, the TSC and TokSys codes are used for analyzing the CFETR vertical instability passive and active controls design simultaneously. It is shown that with the same inputs, the results from these two codes conform with each other.

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Section: Model Comparisonmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comparison benchmark between tokamak simulation code and TokSys for Chinese Fusion Engineering Test Reactor vertical displacement control design

et al. 2017

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“…TokSys, which is well able to estimate vertical growth rates, has been applied to several devices, such as DIII-D [9] and EAST, [5,[10][11][12] and experimentally validated. This gives us the possibility to compare rt-gamma with the result calculated by TokSys directly.…”

Section: Comparisons With Toksysmentioning

confidence: 99%

“…TokSys has been frequently used to calculate growth rate of vertical instability based on rigid plasma response model for the reconstructed plasma equilibrium, [7] which is a key parameter to indicate vertical instability. [10][11][12] Currently, the real-time version of vertical growth rate calculation (rtgamma) has been carried out on EAST, which also adopts rigid plasma response model. [13] The computation of rt-gamma is achieved by linearizing the plasma response around the realtime plasma equilibrium reconstructed by PEFIT.…”

Section: Introductionmentioning

confidence: 99%

Tests of the real-time vertical growth rate calculation on EAST*

et al. 2020

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In order to measure controllability of vertical instability in EAST, the calculation of model-based vertical growth rate, called rt-gamma, has been successfully carried out in real time. The numerical computing method is adapted from rigid plasma response model in TokSys, which is a widely-used analysis tool for tokamak devices in Matlab environment, but the code is rewritten by taking advantage of GPU parallel computing capability to accelerate the computation. The calculation of rt-gamma is validated by comparing it with the corresponding result generated by TokSys for totally 3508 cases. It is shown that the average absolute value of relative errors is about 0.85%. In addition, the calculation program of rt-gamma has been successfully applied during 2019 EAST campaign. The comparison with experimental results is discussed in this paper. The real-time calculation tool is well able to calculate model-based vertical growth rate, which is convenient for fast and continuous evaluations of EAST control system stability performances.

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“…This code has been used on JT-60U [16], ITER [17], and DIII-D [18] for VDErelated analysis. On EAST, this code has been successfully used to reproduce the trajectories of vertical position control by the IC current (I IC ) mode [19]. In 2014, the IC power supply system was upgraded.…”

Section: Introductionmentioning

confidence: 99%

TSC simulation of vertical position control by the Bang-bang method on EAST

et al. 2020

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Vertical instability is a potentially serious hazard for elongated plasma. Many methods have been proposed to control the plasma vertical position. The Bang-bang method, which is designed for the inside coil (IC) voltage mode based on optimal control theory and the RZIp rigid plasma response model, has been successfully used for plasma vertical position control in the EAST 2014 experimental campaign (Wang et al 2016 Fusion Eng. Des. 112 692-8). The Tokamak Simulation Code (TSC) is a numerical model of tokamak plasma and the associated control systems. It studies the evolution of the magnetic field in a rectangular computational domain using the Maxwell magnetohydrodynamic equations for plasma coupled with the boundary conditions to the circuit equations for the poloidal field coils. In this paper, the numerical model of the Bang-bang method has been implemented in the TSC code, which is used to simulate shot 52444. Simulated trajectories of the vertical position, IC voltage, and current fit the experimental data well. On the basis of benchmarked calculation, a numerical investigation of the Bang-bang controller has been performed using the TSC. This controller was able to work with 8 mm random noise and dz = 41.8 mm displacement. As a predictive tool, the TSC code is used to investigate the the maximum controllable vertical displacement value for different maximum current, and evaluate the ability to control the vertical position by the Bang-bang method.

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Simulation of EAST vertical displacement events by tokamak simulation code

Cited by 16 publications

References 25 publications

Comparison benchmark between tokamak simulation code and TokSys for Chinese Fusion Engineering Test Reactor vertical displacement control design

Comparison benchmark between tokamak simulation code and TokSys for Chinese Fusion Engineering Test Reactor vertical displacement control design

Tests of the real-time vertical growth rate calculation on EAST*

TSC simulation of vertical position control by the Bang-bang method on EAST

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