Reduced particle and heat transport with quasisymmetry in the Helically Symmetric Experiment

Canik, J.; Anderson, David T.; Anderson, F. S. B.; Clark, C. W.; Likin, K. M.; Talmadge, J. N.; Zhai, K.

doi:10.1063/1.2709862

Cited by 37 publications

(41 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…More details are given in the papers by Gerhardt [20] and Canik [21]. A common feature of the experiments is that a reduction in neoclassical transport could be observed by altering the magnetic field spectrum, in approximate agreement with theory, but in each case there remained a large level of anomalous transport that didn't appear to change between the configurations.…”

Section: Particle Momentum and Heatmentioning

confidence: 80%

Experimental Tests of Quasisymmetry in HSX

Talmadge

Anderson

et al. 2008

Plasma and Fusion Research

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Section: Particle Momentum and Heatmentioning

confidence: 80%

Experimental Tests of Quasisymmetry in HSX

Talmadge

Anderson

et al. 2008

Plasma and Fusion Research

Self Cite

View full text Add to dashboard Cite

show abstract

“…Thus, reconstruction of the global particle balance may be more feasible as long as the relevant processes happen within the view cone of the camera. In analogy to (11) we can write the integral version of the recycling to re-ionization conversion as where the integrals have to be calculated over the total view cone of the camera V cam and the corresponding observed area on the limiter A cam . Both integrals are evaluated as the sum over all pixels of the camera.…”

Section: Evaluation Of Global Particle Balancementioning

confidence: 99%

“…W7-AS [4,5], W7-X [6,7], LHD [8,9], HSX [10,11]) and tokamaks (e.g. DIII-D [12,13], NSTX [14,15], TEXTOR-DED [16,17]), yet their interpretation in terms of local quantities can be challenging due to line of sight integration effects.…”

Section: Introductionmentioning

confidence: 99%

Reconstruction of recycling flux from synthetic camera images, evaluated for the Wendelstein 7-X startup limiter

et al. 2017

View full text Add to dashboard Cite

Abstract. The interpretation of spectroscopic measurements in the edge region of high-temperature plasmas can be guided by modeling with the EMC3-EIRENE code. A versatile synthetic diagnostic module, initially developed for the generation of synthetic camera images, has been extended for the evaluation of the inverse problem in which the observable photon flux is related back to the originating particle flux (recycling). An application of this synthetic diagnostic to the startup phase (inboard) limiter in Wendelstein 7-X (W7-X) is presented, and reconstruction of recycling from synthetic observation of H α emission is evaluated. It is shown that recycling -in terms of re-ionization within the view cone of the camera -is underestimated by a factor of about 3 at the peak location and overestimated in between, and that H α emission related to molecular dissociation can locally yield an additional factor of 2 for the ionization to photon conversion. Fitted conversion factors are extracted from the simulation results which include a dependence on the plasma density.

show abstract

“…In particular, modular coils which combine toroidal and poloidal field coils into one system are considered to be the most practical solution to the coil problem in quasi-symmetric stellarators. They have been chosen in the design for quasi-axisymmetric stellarators NCSX [3] and ARIES-CS [4], quasi-helically symmetric stellarator HSX [5], quasipoloidally symmetric stellarator QPS [6], and quasi-omnigeneous stellarators W7X [7] and HSR [8]. The geometry for these coils is a complicated function of the shape of the plasma and the location of the coils.…”

Section: Introductionmentioning

confidence: 99%

Modular Coils and Plasma Configurations for Quasi-axisymmetric Stellarators

Boozer¹

2010

View full text Add to dashboard Cite

Characteristics of modular coils for quasi-axisymmetric stellarators that are related to the plasma aspect ratio, number of field periods and rotational transform have been examined systematically. It is observed that, for a given plasma aspect ratio, the coil complexity tends to increase with the increased number of field periods. For a given number of field periods, the toroidal excursion of coil winding is reduced as the plasma aspect ratio is increased. It is also clear that the larger the coil-plasma separation is, the more complex the coils become. It is further demonstrated that it is possible to use other types of coils to complement modular coils to improve both the physics and the modular coil characteristics.

show abstract

Reduced particle and heat transport with quasisymmetry in the Helically Symmetric Experiment

Cited by 37 publications

References 30 publications

Experimental Tests of Quasisymmetry in HSX

Experimental Tests of Quasisymmetry in HSX

Reconstruction of recycling flux from synthetic camera images, evaluated for the Wendelstein 7-X startup limiter

Modular Coils and Plasma Configurations for Quasi-axisymmetric Stellarators

Contact Info

Product

Resources

About