Ideal MHD stability calculations in axisymmetric toroidal coordinate systems

Grimm, R.C.; Dewar, R. L.; Manickam, J.

doi:10.1016/0021-9991(83)90116-x

Cited by 178 publications

(98 citation statements)

References 27 publications

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“…Such a system is not unique and the library constructs three common ones: PEST [37], Hamada [38] and Boozer [39]. The problem is to find expressions for poloidal and toroidal angles θ and ϕ.…”

Section: Magnetic Coordinatesmentioning

confidence: 99%

Service oriented architecture for scientific analysis at W7-X. An example of a field line tracer

Bozhenkov

Geiger

Grahl

et al. 2013

Fusion Engineering and Design

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Section: Magnetic Coordinatesmentioning

confidence: 99%

Service oriented architecture for scientific analysis at W7-X. An example of a field line tracer

Bozhenkov

Geiger

Grahl

et al. 2013

Fusion Engineering and Design

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“…Here the superscript Coord indicates a set of magnetic coordinates, and here so-called PEST coordinates [36] will be used for comparison. PEST coordinates are easy in practice since they are based on an ordinary toroidal angle ϕ = φ.…”

Section: Destruction Of Flux Surfaces and Plasma Lockingmentioning

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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“…JSOLVER recalculates the equilibrium with high resolution for stability analysis. High-n ballooning stability is calculated with BALMSC [11], and n=1 and 2 external kink stability is assessed with PEST2 [12] or DCON [13]. The wall models used in the low-n stability analysis are shown in Fig.…”

Section: Computational Approachmentioning

confidence: 99%

Long pulse high performance plasma scenario development for the National Spherical Torus Experiment

Kessel

Bell

et al. 2006

Physics of Plasmas

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Abstract.The National Spherical Torus Experiment (NSTX) [Ono, M., et al., Nucl. Fusion, 44, (2004), 452.] is targeting long pulse high performance, non-inductive sustained operations at low aspect ratio, and the demonstration of non-solenoidal startup and current rampup. The modeling of these plasmas provides a framework for experimental planning and identifies the tools to access these regimes. Simulations based on NBI (Neutral Beam Injection)-heated plasmas are made to understand the impact of various modifications and identify the requirements for 1) high elongation and triangularity, 2) density control to optimize the current drive, 3) plasma rotation and/or feedback stabilization to operate above the no-wall β limit, and 4) Electron Bernstein Waves (EBW) for off-axis heating/current drive (H/CD). Integrated scenarios are constructed to provide the transport evolution and H/CD source modeling, supported by rf and stability analyses. Important factors include the energy confinement, Z eff , early heating/H-mode, broadening of the NBI-driven current profile, and maintaining q(0) and q min >1.0. Simulations show that non-inductive sustained plasmas can be reached at I P =800 kA, B T =0.5 T, κ≈2.5, β N ≤5, β≤15%, f NI =92%, and q(0)>1.0 with NBI H/CD, density control, and similar global energy confinement to experiments. The non-inductive sustained high β plasmas can be reached at I P =1.0 MA, B T =0.35 T, κ≈2.5, β N ≤9, β≤43%, f NI =100%, and q(0)>1.5 with NBI H/CD and 3.0 2 MW of EBW H/CD, density control, and 25% higher global energy confinement than experiments. A scenario for non-solenoidal plasma current rampup is developed using High Harmonic Fast Wave (HHFW) H/CD in the early low I P and low T e phase, followed by NBI H/CD to continue the current ramp, reaching a maximum of 480 kA after 3.4 s.

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Ideal MHD stability calculations in axisymmetric toroidal coordinate systems

Cited by 178 publications

References 27 publications

Service oriented architecture for scientific analysis at W7-X. An example of a field line tracer

Service oriented architecture for scientific analysis at W7-X. An example of a field line tracer

Importance of plasma response to nonaxisymmetric perturbations in tokamaks

Long pulse high performance plasma scenario development for the National Spherical Torus Experiment

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