A Monte-Carlo model of neutral-particle transport in diverted plasmas

Heifetz, D.; Post, D.; Petravić, M.; Weisheit, Jon C.; Bateman, G.

doi:10.1016/0021-9991(82)90017-1

Cited by 301 publications

(108 citation statements)

References 5 publications

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“…20 Seven of these detectors have been installed around the torus in a toroidal array, while nine of them view the plasma at constant toroidal angle in a vertical array. The neutral gas code DEGAS 21 is used to estimate the density of both atomic and molecular hydrogen in HSX, based on measured H ␣ emission, the electron density profile, 22 and the electron temperature profile. The details of the DEGAS calculation and comparison to the H ␣ measurements will be presented elsewhere.…”

Section: -3mentioning

confidence: 99%

Measurements and modeling of plasma flow damping in the Helically Symmetric eXperiment

et al. 2005

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Fusion Technology 27, 273 ͑1995͔͒ using a biased electrode to impulsively spin the plasma and Mach probes to measure the rotation. There is a distinct asymmetry between the spin-up when the bias is initiated and relaxation when the electrode current is broken. In each case, two time-scales are observed in the evolution of the plasma flow. These observations motivate the development of new neoclassical modeling techniques, including a new model where the fast increment of the electric field initiates the spin-up process. The flow in the quasisymmetric configuration rises more slowly and to a higher value than in a configuration with the quasisymmetry broken, and the rise time-scale is in reasonable agreement with the neoclassical spin-up model. The flows decay more slowly in the quasisymmetry configuration than in the configuration with the quasisymmetry broken, although the decay rates are significantly faster than the neoclassical prediction.

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Section: -3mentioning

confidence: 99%

Measurements and modeling of plasma flow damping in the Helically Symmetric eXperiment

et al. 2005

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“…Both kinetic neutral models such as [9][10][11][12] , and fluid models [13][14][15][16] have previously been applied to study SOL and edge plasmas in the presence of neutrals. In this paper we derive a 2 neutral fluid model for the purpose of studying the effects of neutrals on the intermittent plasma fields.…”

Section: Introductionmentioning

confidence: 99%

Plasma particle sources due to interactions with neutrals in a turbulent scrape-off layer of a toroidally confined plasma

et al. 2018

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The conditions in the edge and scrape-off layer (SOL) of magnetically confined plasmas determine the overall performance of the device, and it is of great importance to study and understand the mechanics that drive transport in those regions. If a significant amount of neutral molecules and atoms is present in the edge and SOL regions, those will influence the plasma parameters and thus the plasma confinement. In this paper, it is displayed how neutrals, described by a fluid model, introduce source terms in a plasma drift-fluid model due to inelastic collisions. The resulting source terms are included in a four-field drift-fluid model, and it is shown how an increasing neutral particle density in the edge and SOL regions influences the plasma particle transport across the last-closed-flux-surface. It is found that an appropriate gas puffing rate allows for the edge density in the simulation to be self-consistently maintained due to ionization of neutrals in the confined region.

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“…For the QHS configuration however, the profile is peaked. The experimental particle flux was inferred from a set of H α detectors and the DEGAS [22] code. Inside r/a ∼ 0.3, the experimental particle flux in the Mirror was found to be close to the neoclassical flux driven by temperature gradients.…”

Section: Particle Momentum and Heatmentioning

confidence: 99%

Experimental Tests of Quasisymmetry in HSX

Talmadge

Anderson

et al. 2008

Plasma and Fusion Research

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This paper discusses the results from experiments in HSX testing the properties of a quasisymmetric stellarator. HSX is a quasihelical stellarator with minimal toroidal curvature and a high effective transform. The high effective transform was verified from passing particle orbits as well as from the magnitude of the Pfirsch-Schlüter and bootstrap currents. The passing particle orbit shift, the helical structure of the Pfirsch-Schlüter current and the direction of the bootstrap current were all consistent with the lack of toroidal curvature. Good agreement was observed between data from plasma currents obtained by a set of magnetic pick-up coils and the results of the V3FIT code. Good confinement of trapped particles was observed with quasisymmetry. These particles may be responsible for a coherent global MHD mode that was detected during ECH at B = 0.5 T. It was found that the breaking of quasisymmetry increased the hollowness of the density profile and the damping of plasma flow while decreasing the core electron temperature, in good agreement with neoclassical models. At 0.5 T, anomalous transport appeared unaffected by the degree of quasisymmetry; more work is need to understand if this still holds at 1.0 T. The experimental energy confinement time and electron temperature profile could be reproduced reasonably well with a combination of neoclassical transport and a modified Weiland model for ITG/TEM turbulence.

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A Monte-Carlo model of neutral-particle transport in diverted plasmas

Cited by 301 publications

References 5 publications

Measurements and modeling of plasma flow damping in the Helically Symmetric eXperiment

Measurements and modeling of plasma flow damping in the Helically Symmetric eXperiment

Plasma particle sources due to interactions with neutrals in a turbulent scrape-off layer of a toroidally confined plasma

Experimental Tests of Quasisymmetry in HSX

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