Dual view FIDA measurements on MAST

Michael, Clive; Conway, N. J.; Crowley, B.; Jones, O.; Heidbrink, W. W.; Pinches, S. D.; Braeken, Eline M. J.; Akers, R.; Challis, C.; Turnyanskiy, M.; Patel, A.; Muir, D.G.; Gaffka, R; Bailey, S. H.

doi:10.1088/0741-3335/55/9/095007

Cited by 51 publications

(65 citation statements)

References 60 publications

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“…There are studies of very low-density plasmas during which the unshifted Balmer-alpha light does not cause too strong saturation of the CCD [e.g., at TCV Geiger et al (2017)], but typically standard CXRS diagnostics used for FIDA are limited to measure either blue or red-shifted FIDA light. As an example, first FIDA measurements at DIII-D (Heidbrink et al 2004;Muscatello et al 2010), ASDEX Upgrade (Geiger 2011), MAST (Michael et al 2013), or LHD (Osakabe et al 2008;Ito 2010;Murakami et al 2008) keep the strong unshifted edge radiation away from the detector chip by focussing only on blue-or red-shifted radiation. Here, it should be noted that LHD used hydrogen as main-ion and fast-ion species.…”

Section: Instrumentationmentioning

confidence: 99%

“…CTS diagnostic based on a far-infrared laser for ion temperature measurements was initially used at the TCA tokamak (Behn et al 1989). Later, the CTS diagnostics at TFTR (Woskoboinikow et al 1983;Machuzak et al 1995), JET (Bindslev 1999a, b), TEXTOR (Bindslev et al 2006;Michelsen 2004), ASDEX Upgrade (Meo et al 2010, Salewski et al 2010, LHD (Nishiura et al 2014;Kubo et al 2010), W7-AS (Suvorov et al 1995), and FTU (Orsitto et al 1999) used microwaves as a source of probing radiation for the fast-ion CTS. The diagnostic is also used for measurements of the ion temperature (Stejner et al 2013(Stejner et al , 2015, isotope ratio (Korsholm et al 2011;Stejner et al 2011Stejner et al , 2013Stejner et al , 2012a, and plasma rotation (Stejner et al 2015(Stejner et al , 2016.…”

Section: Collective Thomson Scatteringmentioning

confidence: 99%

“…Microwave-based CTS for fast-ion studies has been successfully operated on TEXTOR (Bindslev et al 2006;Moseev et al 2011;Nielsen et al 2011Nielsen et al , 2008Nielsen et al , 2010Bindslev et al 2007;Korsholm et al 2010), ASDEX Upgrade (Salewski et al 2010;Nielsen et al 2015;Meo et al 2010Meo et al , 2008Rasmussen et al 2015Rasmussen et al , 2016Jaulmes et al 2016), LHD (Nishiura et al 2014(Nishiura et al , 2010Kubo et al 2010), Wendelstein-7AS (Suvorov et al 1995;Shalashov et al 2003), and FTU (Orsitto et al 1999). TEX-TOR and Wendelstein 7-AS are now out-of-service.…”

Section: Fig 19mentioning

confidence: 99%

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Recent progress in fast-ion diagnostics for magnetically confined plasmas

Moseev

Salewski

García-Muñoz

et al. 2018

Rev. Mod. Plasma Phys.

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On the road to a fusion reactor, a thorough control of the fast-ion distribution plays a crucial role. Fusion-born -particles are, indeed, a necessary ingredient of selfsustained burning plasmas. Recent developments in the diagnostic of fast-ion distributions have significantly improved our predictive capabilities towards future devices. Here, we review key diagnostic techniques for confined and lost fast ions in tokamak and stellarator plasmas. We discuss neutron and gamma-ray spectroscopy, fast-ion D-spectroscopy, collective Thomson scattering, neutral particle analyzers, and fast-ion loss detectors. The review covers physical principles of each diagnostic, sensitivities, basic setups, and operational parameters. The review is largely (but not exclusively) based on the contributions from ASDEX Upgrade and JET. Finally, we discuss integrated data analysis of fast-ion diagnostics by velocity-space tomography which allows measurements of 2D velocity distribution functions of confined fast ions.

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Section: Instrumentationmentioning

confidence: 99%

Section: Collective Thomson Scatteringmentioning

confidence: 99%

Section: Fig 19mentioning

confidence: 99%

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Recent progress in fast-ion diagnostics for magnetically confined plasmas

Moseev

Salewski

García-Muñoz

et al. 2018

Rev. Mod. Plasma Phys.

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“…The signals are especially pronounced when instabilities expel fast ions to the edge [2,3]. Dedicated active FIDA systems on MAST [4] and ASDEX Upgrade [5] also pick up large passive FIDA signals under some conditions. These observations of passive FIDA light are the impetus for the work presented here.…”

Section: Introductionmentioning

confidence: 99%

Measurement and simulation of passive fast-ion D-alpha emission from the DIII-D tokamak

Bolte¹,

Heidbrink²,

Pace³

et al. 2016

Nucl. Fusion

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A sudden loss of fast ions would not only jeopardize plasma performance, but could also-especially in near-reactor conditions-seriously damage the inner wall of the vessel. Accordingly, detection of fast ions near the walls is an important diagnostic challenge.Two types of fast-ion diagnostics utilize charge exchange (CX) reactions between fast ions and neutrals: neutral particle analysis (NPA) and fast-ion D-alpha (FIDA) spectroscopy. A distinction is made between active beam measurements that use CX with injected neutrals and passive measurements that use background neutrals. For active measurements, signals originate near the intersection of the diagnostic sightline with AbstractSpectra of passive fast-ion D-alpha (FIDA) light from beam ions that charge exchange with background neutrals are measured and simulated. The fast ions come from three sources: ions that pass through the diagnostic sightlines on their first full orbit, an axisymmetric confined population, and ions that are expelled into the edge region by instabilities. A passive FIDA simulation (P-FIDASIM) is developed as a forward model for the spectra of the first-orbit fast ions and consists of an experimentally-validated beam deposition model, an ion orbit-following code, a collisional-radiative model, and a synthetic spectrometer. Model validation consists of the simulation of 86 experimental spectra that are obtained using 6 different neutral beam fast-ion sources and 13 different lines of sight. Calibrated spectra are used to estimate the neutral density throughout the cross-section of the tokamak. The resulting 2D neutral density shows the expected increase toward each X-point with average neutral densities of 8 10 cm 9 3 × − at the plasma boundary and 1 10 cm 11 3 × − near the wall. Fast ions that are on passing orbits are expelled by the sawtooth instability more readily than trapped ions. In a sample discharge, approximately 1% of the fast-ion population is ejected into the high neutral density region per sawtooth crash.

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“…In recent years, however, the analysis of fast deuterium ions, i.e. the FIDA method 9 , has become a valuable tool at several fusion devices [10][11][12][13][14][15] . The FIDA method analyzes the strongly Doppler shifted Balmer alpha radiation (λ 0 = 656.1 nm, n = 3 → 2) and makes use of several lines of sight (LOS) that intersect a given NBI path.…”

Section: Introductionmentioning

confidence: 99%

Multi-view fast-ion D-alpha spectroscopy diagnostic at ASDEX Upgrade

Geiger

Dux

McDermott

et al. 2013

Review of Scientific Instruments

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A novel fast-ion D-alpha (FIDA) diagnostic that is based on charge exchange spectroscopy has been installed at ASDEX Upgrade. The diagnostic uses a newly developed high-photon-throughput spectrometer together with a low-noise EM-CCD camera that allow measurements with 2 ms exposure time. Absolute intensities are obtained by calibrating the system with an integrating sphere and the wavelength dependence is determined to high accuracy using a neon lamp. Additional perturbative contributions to the spectra, such as D 2 -molecular lines, the Stark broadened edge D-alpha emission, and passive FIDA radiation have been identified and can be subtracted or avoided experimentally. The FIDA radiation from fast deuterium ions after charge exchange reactions can therefore be analyzed continuously without superimposed line emissions at large Doppler shifts. Radial information on the fast ions is obtained from radially distributed lines of sight. The investigation of the fast-ion velocity distribution is possible due to three different viewing geometries. The independent viewing geometries access distinct parts of the fast-ion velocity space and make tomographic reconstructions possible.

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Dual view FIDA measurements on MAST

Cited by 51 publications

References 60 publications

Recent progress in fast-ion diagnostics for magnetically confined plasmas

Recent progress in fast-ion diagnostics for magnetically confined plasmas

Measurement and simulation of passive fast-ion D-alpha emission from the DIII-D tokamak

Multi-view fast-ion D-alpha spectroscopy diagnostic at ASDEX Upgrade

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