A 6 MeV heavy ion beam probe for the Large Helical Device

Fujisawa, A.; Iguchi, H.; Taniike, Akira; Sasao, M.; Hamada, Y.

doi:10.1109/27.310646

Cited by 28 publications

(9 citation statements)

References 26 publications

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“…The outcome of the two measurements agrees to within 10% of the radial electric field [58]. The same scientific group is presently commissioning the most comprehensive HIBP system that is installed at the LHD heliac [59]. This system features a Au + beam which is accelerated up to 6 MeV by a tandem Van de Graaff accelerator.…”

Section: Heavy Ion Beam Probementioning

confidence: 89%

Diagnostics for current density and radial electric field measurements: overview and recent trends

Donné

2002

Plasma Phys. Control. Fusion

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The measurements of the current density and the radial electric field profiles in tokamaks have considerably gained importance since advanced operational scenarios have come into play. A detailed knowledge of these profiles is desirable for operational scenarios involving reversed magnetic shear and/or the active control of internal and edge transport barriers. Unfortunately, the current density as well as the radial electric field are among the plasma parameters that are most difficult to diagnose. Routine methods to measure the current density profile are based on the Faraday effect (i.e. polarimetry) and the motional Stark effect (MSE). The most advanced diagnostics for the measurement of the radial electric field in the plasma core are the heavy ion beam probe and again the MSE. This paper will briefly explain the need for detailed measurements of the current density and radial electric field profile. Subsequently, the various diagnostics to measure these parameters will be reviewed. The emphasis will be especially put on recent trends, rather than on an exhaustive overview.

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Section: Heavy Ion Beam Probementioning

confidence: 89%

Diagnostics for current density and radial electric field measurements: overview and recent trends

Donné

2002

Plasma Phys. Control. Fusion

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“…The maximum of error in potential measurement is 50 eV, and the error can be corrected in the potential profiles. The loss of beam energy through collisions with plasma particles might cause an error, but it is estimated to be < 10 eV [24] because the plasma density is low. In previous HIBPs, the radiation from plasmas caused errors occasionally because it produced photoelectrons in the beam line, which caused drops in the sweep and analyzer voltages and pseudo signals in the detectors.…”

Section: Error Estimationmentioning

confidence: 99%

“…Therefore, understanding the behavior of E r and its effects on transport is important for predicting the performance of future fusion plasmas. To achieve this, an HIBP has been developed for Large Helical Device (LHD) [24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Electrostatic Potential Measurement by Using 6-MeV Heavy Ion Beam Probe on LHD

Ido

Shimizu

Nishiura

et al. 2008

Plasma and Fusion Research

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A heavy ion beam probe (HIBP) using a 3 MV tandem accelerator was installed in Large Helical Device (LHD). It is designed to measure the electrostatic potential in the core region directly. It is calibrated and can be used to measure the electrostatic potential profiles in LHD plasmas. The radial electric field (E r ) obtained from the potential profiles measured using the HIBP agrees with that measured by charge exchange spectroscopy (CXS). E r predicted by the neoclassical theory is also compared to that measured using the HIBP, and is in good agreement with the experimental results in the core region.

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“…In the basic design phase of LHD-HIBP system, the ratios of primary beam current to secondary beam current are predicted by taking into account only the electronimpact ionization processes [1]. In absence of experimental cross sections, the Lotz formula [2] was used to determine the cross sections of Au + and Au 2+ for electron impact ionization.…”

Section: Introductionmentioning

confidence: 99%

Electron Loss Cross Sections for a Heavy Ion Beam Probe

Nishiura

Ido

Shimizu

et al. 2007

Plasma and Fusion Research

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Electron loss cross sections of Au+ and Au 2+ by electron and proton impact are calculated by using respectively the Lotz formula and the LOSS and CAPTURE computer codes. The corresponding rate coefficients have also been calculated. Using this information, the signal levels of heavy ion beam probe in the Large Helical Device are estimated. The calculated beam currents at the detector position are compared with the detected beam currents in the MeV energy range for a plasma electron density of 1 × 10 19 m −3 and electron temperature of 1.5 keV. The obtained cross section / rate coefficient data can also be used for reconstruction of electron density and temperature profiles.

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A 6 MeV heavy ion beam probe for the Large Helical Device

Cited by 28 publications

References 26 publications

Diagnostics for current density and radial electric field measurements: overview and recent trends

Diagnostics for current density and radial electric field measurements: overview and recent trends

Electrostatic Potential Measurement by Using 6-MeV Heavy Ion Beam Probe on LHD

Electron Loss Cross Sections for a Heavy Ion Beam Probe

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