Experimental Studies of Plasma Confined in a Toroidal Heliac

Blackwell, B. D.; Hamberger, S.M.; Sharp, L. E.; Shi, Xiaojian

doi:10.1071/ph890073

Cited by 13 publications

(7 citation statements)

References 11 publications

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“…In SHEILA, the rotational transform ͑ϵ1/q, with q being safety factor͒ varies from 1.2 at the magnetic axis to 1.4 at the outermost flux surface for the standard magnetic field configuration of SHEILA. 15 This standard configuration is used exclusively during the experiments, and the radial variation of is considered in this work.…”

Section: Experimental Arrangementmentioning

confidence: 99%

“…The magnetic configuration of the prototype heliac SHEILA 14,15 consists of a bean-shaped cross section twisting around its ring conductor three times toroidally, the magnetic axis following an mϭ1 helix. Figures 1͑a͒, 1͑b͒ show a typical vacuum magnetic flux surface in a heliac, and the flux surface cross section of SHEILA at four different toroidal angles within one field period ͑ϭ0°, 30°, 60°and 90°͒, respectively.…”

Section: Experimental Arrangementmentioning

confidence: 99%

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Observation of the neoclassical current in the Small Heliac Experimental Apparatus (SHEILA)

et al. 1997

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The first measurements of internal currents in a toroidal heliac are reported. It is suggested that the toroidal current observed in the Small Heliac Experimental Apparatus (SHEILA) [Nucl. Fusion 25, 1485 (1985)] in the low density regime consists mainly of the bootstrap current and the Pfirsch–Schlüter current, the net toroidal component corresponding to the uni-directional bootstrap current, and the asymmetric radial profile of the observed current indicating a mixture of bootstrap current with the bi-directional Pfirsch–Schlüter current.

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Section: Experimental Arrangementmentioning

confidence: 99%

Section: Experimental Arrangementmentioning

confidence: 99%

Observation of the neoclassical current in the Small Heliac Experimental Apparatus (SHEILA)

et al. 1997

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“…The average radius of the helix is 14.3 mm, with random deviations of up to ±1 mm. The parameters and construction of the apparatus are described more fully in Refs [1,5].…”

Section: Vacuum Field Configurationsmentioning

confidence: 99%

Experimental investigation of different configurations in a flexible heliac

1988

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The effect of varying the magnetic field configuration by adding an ℓ = 1 helical winding to the standard heliac has been studied experimentally. Equilibrium plasma configurations in the range 0.7 ≤ t(0) ≤ 1.86 have been obtained. Analyses of the plasma pressure profiles measured by Langmuir probes in this range show good agreement between the plasma isobars and the computed vacuum magnetic surfaces; for configurations with a rotational transform t(0) close to unity it is necessary to take known error fields into account. When low-order rational surfaces are present, a deterioration of the plasma confinement is clearly observed. Magnetic islands, resulting from the resonance between the low-order rational surface ι = 3/2 and the m = 2, n = 3 vacuum field harmonics inherent in the geometry, are identified with features observed in both the plasma pressure and the floating potential profiles.

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“…SHEILA is a small prototype heliac stellarator (Blackwell et al 1989). Its magnetic configuration is composed of a bean-shaped cross-section twisting around a ring conductor three times toroidally, and its magnetic axis follows an ra = 1 helix.…”

Section: Current and Transport Induced By Fluctuating Fieldsmentioning

confidence: 99%

“…The ratio B og /B Oz of the poloidal component of the magnetostatic field to the toroidal one for the standard configuration is -03. The major radius of SHEILA is 0-19 m and the averaged minor radius is 0-035 m. The magnetic field B o is up to 0-18 T in a pulse of 55 ms. For further details, we refer to Blackwell et al (1989). Shi et al (1989) studied low-frequency and highly coherent fluctuations.…”

Section: Current and Transport Induced By Fluctuating Fieldsmentioning

confidence: 99%