Fluctuations and stability of plasmas in the H-1NF heliac

Harris, J. H.; Shats, Michael; Blackwell, Boyd; Solomon, W. M.; Pretty, D. G.; Collis, Scott; Howard, J.; Xia, Hua; Michael, Clive; Punzmann, Horst

doi:10.1088/0029-5515/44/2/008

Cited by 18 publications

(22 citation statements)

References 29 publications

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“…The effect of the rotational transform on the plasma confinement and peak density in H-1 has been previously reported. 6 We have extended this study by utilizing the capabilities of ELSI to observe details of the plasma density projections as a function of the rotational transform ͑͒. In particular we have noted a strong link between the radial position of the steepest density gradient and the location of low-order rational surfaces = n / m within the plasma volume.…”

Section: B Magnetic Configuration Studiesmentioning

confidence: 77%

Three view electronically scanned interferometer for plasma electron density measurements on the H-1 heliac

Oliver

Howard²,

Kumar³

et al. 2006

Review of Scientific Instruments

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We report the development of a three view electronically scanned millimeter-wave interferometer for plasma electron density profile measurement on the H-1 heliac. The system utilizes an electronically tunable backward-wave oscillator whose output is incident on a fixed blazed diffraction grating such that sweeping the source frequency effects a spatial scan of the plasma cross section. Two diagonal views essentially span most of the plasma cross section, while the horizontal arm views the lower half of the plasma. The diffracted beams traverse the plasma in Ͻ1 ms with a spatial resolution ϳ20 mm. A study of the density projection dependence on magnetic configuration shows that the presence of low-order rational surfaces in the plasma gives rise to sharp density gradients in the vicinity of the surface.

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Section: B Magnetic Configuration Studiesmentioning

confidence: 77%

Three view electronically scanned interferometer for plasma electron density measurements on the H-1 heliac

Oliver

Howard²,

Kumar³

et al. 2006

Review of Scientific Instruments

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“…Such features are seen both at < 1 in "traditional" stellarators (Carreras et al, 1988) and in heliacs at > 1 (Herranz et al, 2000;Alejaldre et al, 2001;Harris et al, 2004). Fine-scale Thomson scattering studies of profiles in the RTP tokamak (Lopes- Cardozo et al, 1997) show similar phenomena.…”

Section: Resonant Magnetic Surfacesmentioning

confidence: 90%

Small to mid-sized stellarator experiments: topology, confinement and turbulence

Harris¹

2004

Plasma Phys. Control. Fusion

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The very large stellarator experiments LHD (operating) and W7X (under construction) move stellarator-confined plasmas into the near-reactor regime. Continuing experiments on smaller devices operating at heating powers from kW to a few MW are exploring the effects of magnetic configuration stability and turbulence on plasma confinement to improve stellarator performance and our understanding of general toroidal confinement physics. Key issues being explored are the relation of rational magnetic surfaces and magnetic configuration characteristics such as helical ripple to plasma transport, confinement scaling and turbulence. The robust macroscopic stability of currentless stellarator plasma is a major contributing factor to theses studies. Many of the phenomena most clearly evident in stellarators are increasingly implicated in tokamak experiments as well.

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“…A linear plasma device NUMBER (Nagoya University Magnetoplasma Basic Experiment) was designed and constructed to develop a new method of generating energetic ions. Target values of the electron density and the electron temperature are ∼ 1 × 10 18 m −3 and ∼ 10 eV, respectively, corresponding to those achieved in small stellarators [1][2][3][4]. Other requirements for the device are a uniform magnetic field of about 0.3 T and a large (> 0.05 m) diameter of plasma column.…”

Section: Introductionmentioning

confidence: 97%

Magnetic Field Configuration Dependence of Plasma Production and Parallel Transport in a Linear Plasma Device NUMBER

Hamada

Okamoto

Fujita

et al. 2018

Plasma and Fusion Research

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In order to study a new method of generating energetic ion, a linear plasma device NUMBER was designed and constructed. The device consists of a plasma production region and a test region connected axially. The radial profile of the electron density and the electron temperature were measured using a Langmuir probe. The radius of plasma is consistent with a field line trace calculation. The time evolution of the ion saturation current I is was measured. A high I is phase accompanied by rapid increase and rapid decrease of I is was observed. From the scan of magnetic field in the test region, it is found that the high I is phase may be caused by unexpected electron cyclotron resonance in the test region. The gas pressure is also related to the appearance of the high I is phase.

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Fluctuations and stability of plasmas in the H-1NF heliac

Cited by 18 publications

References 29 publications

Three view electronically scanned interferometer for plasma electron density measurements on the H-1 heliac

Three view electronically scanned interferometer for plasma electron density measurements on the H-1 heliac

Small to mid-sized stellarator experiments: topology, confinement and turbulence

Magnetic Field Configuration Dependence of Plasma Production and Parallel Transport in a Linear Plasma Device NUMBER

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