Comparing TCV experimental VDE responses with DINA code simulations
- 21 December 2001
- journal article
- Published by IOP Publishing in Plasma Physics and Controlled Fusion
- Vol. 44 (2), 171-193
- https://doi.org/10.1088/0741-3335/44/2/303
Abstract
The DINA free-boundary equilibrium simulation code has been implemented for TCV, including the full TCV feedback and diagnostic systems. First results showed good agreement with control coil perturbations and correctly reproduced certain non-linear features in the experimental measurements. The latest DINA code simulations, presented in this paper, exploit discharges with different cross-sectional shapes and different vertical instability growth rates which were subjected to controlled vertical displacement events (VDEs), extending previous work with the DINA code on the DIII-D tokamak. The height of the TCV vessel allows observation of the non-linear evolution of the VDE growth rate as regions of different vertical field decay index are crossed. The vertical movement of the plasma is found to be well modelled. For most experiments, DINA reproduces the S-shape of the vertical displacement in TCV with excellent precision. This behaviour cannot be modelled using linear time-independent models because of the predominant exponential shape due to the unstable pole of any linear time-independent model. The other most common equilibrium parameters like the plasma current Ip, the elongation κ, the triangularity δ, the safety factor q, the ratio between the averaged plasma kinetic pressure and the pressure of the poloidal magnetic field at the edge of the plasma βp, and the internal self inductance li also show acceptable agreement. The evolution of the growth rate γ is estimated and compared with the evolution of the closed-loop growth rate calculated with the RZIP linear model, confirming the origin of the observed behaviour.Keywords
This publication has 9 references indexed in Scilit:
- Comparing DINA code simulations with TCV experimental plasma equilibrium responsesPlasma Physics and Controlled Fusion, 2001
- Vertical position control in TCV: Comparison of model predictions with experimental resultsNuclear Fusion, 2000
- Measurement of the open loop plasma equilibrium response in TCVNuclear Fusion, 1999
- Stability analysis of the vertical position control loop in TCV using rigid and deformable plasma modelsNuclear Fusion, 1998
- The linearized CREATE-L plasma response model for the control of current, position and shape in tokamaksNuclear Fusion, 1998
- Vertical instability in TCV: comparison of experimental and theoretical growth ratesNuclear Fusion, 1997
- Studies of Plasma Equilibrium and Transport in a Tokamak Fusion Device with the Inverse-Variable TechniqueJournal of Computational Physics, 1993
- Tokamak equilibrium reconstruction using Faraday rotation measurementsNuclear Fusion, 1988
- Dynamic modeling of transport and positional control of tokamaksJournal of Computational Physics, 1986