The CHEASE code for toroidal MHD equilibria

Lütjens, H.; Bondeson, A.; Sauter, O.

doi:10.1016/0010-4655(96)00046-x

Cited by 346 publications

(393 citation statements)

References 20 publications

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“…The starting equilibrium is computed using the CHEASE code. 28 The equilibrium boundary is circular, with aspect ratio R 0 =a ¼ 2.7. The pressure and magnetic q profiles used for the study are shown in Fig.…”

Section: A Set Up Of Physical Parameters For the Simulationsmentioning

confidence: 99%

Diamagnetic thresholds for sawtooth cycling in tokamak plasmas

2011

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The cycling dynamics of the internal kink mode, which drives sawtooth oscillations in tokamak plasmas, is studied using the three dimensional, non-linear magnetohydrodynamic (MHD) code XTOR-2F [H. Lütjens and J.-F. Luciani, J. Comput. Phys. 229, 8130 (2010)]. It is found that sawtooth cycling, which is characterized by quiescent ramps and fast crashes in the experiment, can be recovered in two-fluid MHD provided that a criterion of diamagnetic stabilization is fulfilled. The simulation results indicate that diamagnetic effects alone may be sufficient to drive sawteeth with complete magnetic reconnection in high temperature Ohmic plasmas.

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Section: A Set Up Of Physical Parameters For the Simulationsmentioning

confidence: 99%

Diamagnetic thresholds for sawtooth cycling in tokamak plasmas

2011

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“…The validity of the model for plasma geometry is tested comparing the analytical values of the operators ٌ͉͗⌿͉ 2 ͘ and ͉͗v D · ٌ⌿͉ 2 ͘ with the values computed by the equilibrium solver code CHEASE, 17 on the case q s ͑ = 0.5͒ = 1.44, where = r / a. According to this picture, the choice of the elongation function E͑r͒ = r͑ s −1͒ is quite a rough approximation of an ideal MHD equilibrium, with constant elongation across magnetic surfaces, as can be seen writing it explicitly,…”

Section: Study Of the Validity Of The Approximation Of The Geometrymentioning

confidence: 99%

The role of plasma elongation on the linear damping of zonal flows

Angelino

Garbet

Villard³

et al. 2008

Physics of Plasmas

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Drift wave turbulence is known to self-organize to form axisymmetric macroscopic flows. The basic mechanism for macroscopic flow generation is called inverse energy cascade. Essentially, it is an energy transfer from the short wavelengths to the long wavelengths in the turbulent spectrum due to nonlinear interactions. A class of macroscopic flows, the poloidally symmetric zonal flows, is widely recognized as a key constituent in nearly all cases and regimes of microturbulence, also because of the realization that zonal flows are a critical agent of self-regulation for turbulent transport. In tokamaks and other toroidal magnetic confinement systems, axisymmetric flows exist in two branches, a zero frequency branch and a finite frequency branch, named Geodesic Acoustic Modes ͑GAMs͒. The finite frequency is due to the geodesic curvature of the magnetic field. There is a growing body of evidence that suggests strong GAM activity in most devices. Theoretical investigation of the GAMs is still an open field of research. Part of the difficulty of modelling the GAMs stems from the requirement of running global codes. Another issue is that one cannot determine a simple one to one relation between turbulence stabilization and GAM activity. This paper focuses on the study of ion temperature gradient turbulence in realistic tokamak magnetohydrodynamic equilibria. Analytical and numerical analyses are applied to the study of geometrical effects on zonal flows oscillations. Results are shown on the effects of the plasma elongation on the GAM amplitude and frequency and on the zonal flow residual amplitude.

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“…The ion distribution functions were calculated with the SELFO-light code [6], in which the equilibrium, calculated with the CHEASE code [7], is separated into a set of shells limited by magnetic flux surfaces, here denoted as subvolumes. The wave field is calculated with the LION code [8,9] and the time dependent distribution functions with a 1D Fokker-Planck code [10].…”

Section: Simulations Of Jet Experimentsmentioning

confidence: 99%

RF heating for fusion product studies

2015

AIP Conference Proceedings

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Third harmonic cyclotron heating is an effective tool for accelerating deuterium (D) beams to the MeV energy range, suitable for studying ITER relevant fast particle physics in plasmas without significant tritium content. Such experiments were recently conducted in JET with an ITER like wall in D plasmas with 3He concentrations up to 30% in order to boost the fusion reactivity by D-3He reactions. The harmonic cyclotron heating produces high-energy tails in the MeV range of D ions by on-axis heating and of 3He ions by tangential off-axis heating. The discharges are characterized by long sawtooth free periods and a rich spectrum of MHD modes excited by the fast D and 3He ions. The partitions of the power, which depend on the distribution function of D, vary strongly over several slowing down times. Self-consistent modelling of the distribution function with the SELFO-light code are presented and compared with experimental data from fast particle diagnostics.This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission.Peer ReviewedPostprint (published version

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The CHEASE code for toroidal MHD equilibria

Cited by 346 publications

References 20 publications

Diamagnetic thresholds for sawtooth cycling in tokamak plasmas

Diamagnetic thresholds for sawtooth cycling in tokamak plasmas

The role of plasma elongation on the linear damping of zonal flows

RF heating for fusion product studies

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