Computation of three-dimensional tokamak and spherical torus equilibria

Park, Jong‐Kyu; Boozer, Allen H.; Glasser, A. H.

doi:10.1063/1.2732170

Cited by 201 publications

(227 citation statements)

References 19 publications

(16 reference statements)

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“…The Ideal Perturbed Equilibrium Code (IPEC) [26], which is based on the DCON [27] and the VACUUM [28] stability codes, solves free-boundary ideal perturbed equilibria preserving the pressure p(ψ) and the safety factor q(ψ) profiles. The fixed q(ψ) profile means that no topological changes in magnetic field lines are allowed, so magnetic islands are always shielded.…”

Section: Ideal Perturbed Equilibriummentioning

confidence: 99%

Importance of plasma response to nonaxisymmetric perturbations in tokamaks

et al. 2009

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Tokamaks are sensitive to deviations from axisymmetry as small as δB/B 0 ∼ 10 −4 . These non-axisymmetric perturbations greatly modify plasma confinement and performance by either destroying magnetic surfaces with subsequent locking or deforming magnetic surfaces with associated non-ambipolar transport. The Ideal Perturbed Equilibrium Code (IPEC) calculates ideal perturbed equilibria and provides important basis for understanding the sensitivity of tokamak plasmas to perturbations. IPEC calculations indicate that the ideal plasma response, or equivalently the effect by ideally perturbed plasma currents, is essential to explain locking experiments on National Spherical Torus eXperiment (NSTX) and DIII-D. The ideal plasma response is also important for Neoclassical Toroidal Viscosity (NTV) in non-ambipolar transport. The consistency between NTV theory and magnetic braking experiments on NSTX and DIII-D can be improved when the variation in the field strength in IPEC is coupled with generalized NTV theory. These plasma response effects will be compared with the previous vacuum superpositions to illustrate the importance. However, plasma response based on ideal perturbed equilibria is still not sufficiently accurate to predict the details of NTV transport, and can be inconsistent when currents associated with a toroidal torque become comparable to ideal perturbed currents.

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Section: Ideal Perturbed Equilibriummentioning

confidence: 99%

Importance of plasma response to nonaxisymmetric perturbations in tokamaks

et al. 2009

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“…Under fixed externally applied RMP fields, the present study includes most of the relevant transport physics selfconsistently, but assumes that the electrostatic potential Φ variations within a flux surface and the RMP-induced changes to turbulence transport are negligible. Plasma screening is suspected to play an important role in the actual RMP distribution, but is difficult to calculate [17][18][19][20][21]. Numerical simulation of plasma screened RMPs, self-consistently with kinetic plasma dynamics, electric field response and plasma rotation, is currently under invetigation and will be a subject of a future report.…”

Section: Introductionmentioning

confidence: 99%

Plasma transport in stochastic magnetic field caused by vacuum resonant magnetic perturbations at diverted tokamak edge

et al. 2010

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A kinetic transport simulation for the first 4 ms of the vacuum resonant magnetic perturbations (RMPs) application has been performed for the first time in realistic diveted DIII-D tokamak geometry [J. Luxon, Nucl. Fusion 42, 614 (2002)], with the self-consistent evaluation of the radial electric field and the plasma rotation. It is found that, due to the kinetic effects, the stochastic parallel thermal transport is significantly reduced when compared to the standard analytic model

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“…A tokamak plasma responds to a nonaxisymmetric magnetic perturbation by producing perturbed plasma currents. These currents can fundamentally change the magnetic perturbation as shown in the calculations of perturbed scalar pressure equilibria using Ideal Perturbed Equilibrium Code (IPEC) [7], and in the IPEC applications to plasma locking experiments [8,9].…”

Section: Introductionmentioning

confidence: 99%

Shielding of external magnetic perturbations by torque in rotating tokamak plasmas

et al. 2009

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The imposition of a nonaxisymmetric magnetic perturbation on a rotating tokamak plasma requires energy and toroidal torque. Fundamental electrodynamics implies that the torque is essentially limited and must be consistent with the external response of a plasma equilibrium f = j × B.Here magnetic measurements on National Spherical Torus eXperiment (NSTX) device are used to derive the energy and the torque, and these empirical evaluations are compared with theoretical calculations based on perturbed scalar pressure equilibria f = ∇p coupled with the theory of nonambipolar transport. The measurement and the theory are consistent within acceptable uncertainties, but can be largely inconsistent when the torque is comparable to the energy. This is expected since the currents associated with the torque are ignored in scalar pressure equilibria, but these currents tend to shield the perturbation.

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Computation of three-dimensional tokamak and spherical torus equilibria

Cited by 201 publications

References 19 publications

Importance of plasma response to nonaxisymmetric perturbations in tokamaks

Importance of plasma response to nonaxisymmetric perturbations in tokamaks

Plasma transport in stochastic magnetic field caused by vacuum resonant magnetic perturbations at diverted tokamak edge

Shielding of external magnetic perturbations by torque in rotating tokamak plasmas

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