Grazing-incidence spectrometer on the SSPX spheromak

Clementson, J.; Beiersdörfer, P.; Magee, E. W.

doi:10.1063/1.2965776

Cited by 12 publications

(3 citation statements)

References 22 publications

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“…A high-resolution grazing-incidence spectrometer was used to study the tungsten emission. The same instrument has previously been used to study titanium and low-Z plasma impurities on SSPX [29][30][31][32] and is described in detail in [33]. For this experiment, the spectrometer was equipped with a Photometrics back-illuminated charge-coupled device (CCD) detector and a 30 μm entrance slit.…”

Section: Methodsmentioning

confidence: 99%

Tungsten spectroscopy relevant to the diagnostics of ITER divertor plasmas

Clementson¹,

Beiersdörfer

Magee

et al. 2010

J. Phys. B: At. Mol. Opt. Phys.

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The possibility of using extreme ultraviolet emission from low charge states of tungsten ions to diagnose the divertor plasmas of the ITER tokamak has been investigated. Spectral modelling of Lu-like W 3+ to Gd-like W 10+ has been performed by using the Flexible Atomic Code, and spectroscopic measurements have been conducted at the Sustained Spheromak Physics Experiment (SSPX) in Livermore. To simulate ITER divertor plasmas, tungsten was introduced into the SSPX spheromak by prefilling it with tungsten hexacarbonyl prior to the usual hydrogen gas injection and initiation of the plasma discharge. The tungsten emission was studied using a grazing-incidence spectrometer.

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Section: Methodsmentioning

confidence: 99%

Tungsten spectroscopy relevant to the diagnostics of ITER divertor plasmas

Clementson¹,

Beiersdörfer

Magee

et al. 2010

J. Phys. B: At. Mol. Opt. Phys.

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“…The spectra were studied using a moderate-resolution broad-band grating spectrometer of the same type used for grazing-incidence measurements at the SSPX, NSTX, LTX and Alcator C-Mod magnetic fusion facilities [42][43][44][45][46][47]. The instrument employs a 1200-line/mm flat-field grating with a radius of curvature of 5.6 m. The diffracted rays are focused on a Princeton Instruments back-illuminated CCD camera with a 1024 × 1340 array of pixels, each of a size of 20 µm × 20 µm.…”

Section: Survey Measurementsmentioning

confidence: 99%

Extreme Ultraviolet Spectra of Few-Times Ionized Tungsten for Divertor Plasma Diagnostics

Clementson

Lennartsson

Beiersdörfer

2015

Atoms

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The extreme ultraviolet (EUV) emission from few-times ionized tungsten atoms has been experimentally studied at the Livermore electron beam ion trap facility. The ions were produced and confined during low-energy operations of the EBIT-I electron beam ion trap. By varying the electron-beam energy from around 30-300 eV, tungsten ions in charge states expected to be abundant in tokamak divertor plasmas were excited, and the resulting EUV emission was studied using a survey spectrometer covering 120-320 Å. It is found that the emission strongly depends on the excitation energy; below 150 eV, it is relatively simple, consisting of strong isolated lines from a few charge states, whereas at higher energies, it becomes very complex. For divertor plasmas with tungsten impurity ions, this emission should prove useful for diagnostics of tungsten flux rates and charge balance, as well as for radiative cooling of the divertor volume. Several lines in the 194-223 Å interval belonging to the spectra of five-and seven-times ionized tungsten (Tm-like W VI and Ho-like W VIII) were also measured using a high-resolution spectrometer.

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“…Then, the impurity radiation intensity can be calculated, and its impact on the main plasma is evaluated based on the results of the main plasma internal energy calculation. Extreme ultraviolet (EUV) spectroscopy offers an excellent tool for surveying impurity line radiation of core region in high-temperature plasma and has been used on many fusion devices [14][15][16][17][18][19]. Vacuum ultraviolet (VUV) spectrometers with the wavelength range of 50-460 nm are usually chosen as diagnoses for impurity radiations measurement at edge region of various fusion devices [20][21][22][23][24][25][26] and also planned for ITER [27].…”

Section: Introductionmentioning

confidence: 99%

Vacuum-Ultraviolet spectrometer system for impurity emission measurement on a Compact Torus Injection System of EAST

Shen,

Niu,

Kong

et al. 2024

J. Inst.

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Recently, a compact torus injection (CTI) system was developed for central fueling on experimental advanced superconducting tokamak (EAST). As impurity generated by the interaction between CTI plasma and the electrode material can dilute the fuel particle, it is important to measure impurity content in CTI and evaluate the effect of impurity on the plasma before the application of CTI to EAST. A vacuum-ultraviolet (VUV) spectrometer that utilizes a concave holographic grating with 1200 groove mm-1 was developed and installed on EAST-CTI for impurity emission measurement and transport study. The mainly parts of the spectrometer are an entrance slit, a concave holographic grating with 1200 groove mm-1 and a charge coupled device (CCD). The spectrometer is designed to image the spectra of 50–460 nm by turning the grating. Preliminary experimental results were obtained from the recent EAST-CTI campaign. Impurity line spectra from 50 to 460 nm wavelength range were measured and identified for several impurity species, such as iron, copper, chromium, oxygen, carbon and fluorine. For example, spectra in the intervals of 150 nm to 300 nm contained strong Fe lines. Helium spectra are also measured in the form of He I and He II spectral lines as helium is the main component of the plasma. The results show that the VUV spectrometer is capable of measuring impurity radiations on EAST-CTI and will be a useful tool for impurity behavior study.

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Grazing-incidence spectrometer on the SSPX spheromak

Cited by 12 publications

References 22 publications

Tungsten spectroscopy relevant to the diagnostics of ITER divertor plasmas

Tungsten spectroscopy relevant to the diagnostics of ITER divertor plasmas

Extreme Ultraviolet Spectra of Few-Times Ionized Tungsten for Divertor Plasma Diagnostics

Vacuum-Ultraviolet spectrometer system for impurity emission measurement on a Compact Torus Injection System of EAST

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