Measurement of Absolute Carbon Ion Density Profile Based on CXRS Diagnostic on HL-2A Tokamak

Liu, Liang; Yu, D.L.; Wei, Y. L.; Liu, Dong; Chen, Wenjin; He, Xiaoxue; Zhang, N.; Yang, Z.C.; Li, Yonggao; Yan, L.W.; Shi, Z.B.; Liu, Yi; Qi, Yang

doi:10.1585/pfr.15.2402055

Cited by 2 publications

(3 citation statements)

References 14 publications

(15 reference statements)

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“…The change indicates that there is an outward transport in carbon impurity. [38] The underlying mechanism of impurity transport is beyond the scope here. It is well known that core localization of impurity usually contributes to the formation of reversed shear plasma.…”

Section: √︀mentioning

confidence: 97%

Observation and Simulation of n = 1 Reversed Shear Alfvén Eigenmode on the HL-2A Tokamak

Shi

Yang

Chen

et al. 2022

Chinese Phys. Lett.

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A branch of high frequency Alfvénic mode is observed on the HL-2A tokamak. The electromagnetic mode can be driven unstable in the plasma with an off-axis neutral beam heating. Its mode frequency keeps almost unchanged or presents a slow-sweeping behavior, depending on the detail current evolution. The poloidal and toroidal mode numbers are $m/n=1/1$. The mode has a quite short duration ($\leq20 $ ms) and usually appears 5-10 ms after the neutral beam being injected into the plasma. Hybrid simulations based on M3D-K have also been carried out. The result suggests that co-passing energetic particles are responsible for the mode excitation. The simulated mode structures are localized nearby location of minimum safety factor ($q_{min}$) and agree with the structures obtained through tomography of soft x-ray arrays. Further, the modes are localized in the continuum gap and their frequencies increase with variation of $q_{min}$ in a wide range. Last but not least, the characteristic of unchanged frequency on experiment is also reproduced by the nonlinear simulation with a fixed safety factor. All those evidences indicate that the $n=1$ high frequency mode may belong to a reversed shear Alfvén eigenmode (RSAE).

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Section: √︀mentioning

confidence: 97%

Observation and Simulation of n = 1 Reversed Shear Alfvén Eigenmode on the HL-2A Tokamak

Shi

Yang

Chen

et al. 2022

Chinese Phys. Lett.

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“…For a given spectral line, the images for different spatial channels are not in a column. The curvature shown in figures 3(a)-(c) arises from (vertically) off-axis illumination of the grating by fibers above and below the center of the array [17]; to measure the velocity correctly, each fiber position will be calibrated by the standard lamps. Furthermore, HL-2A has radially installed fiber bundles collecting the lights from plasma, making sure that the He II and C VI can be monitored with negligible Doppler shift with respective to the standstill ones.…”

Section: Calibration Of the Reciprocal Linear Dispersionmentioning

confidence: 99%

“…The design and construction of the spectrometer was started in 2014. Inspired by the introductions of the transmission gratings [16,17], the initial idea was to construct the multi-band spectrometer with angles between the incident and the output lights around 90 degrees. However, the incident/diffracted angles were finally updated to be ~62 degrees by considering the dispersions, the cost and the simplicity of the structure.…”

Section: Introductionmentioning

confidence: 99%

The tri-band high spectral resolution spectrometer with gratings in tandem for the charge-exchange recombination spectroscopy diagnostic system on HL-2A tokamak

LIU 刘,

YU 余,

MA 马

et al. 2024

Plasma Sci. Technol.

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Charge-exchange (CX) recombination spectroscopy is a powerful tool monitoring ion temperature and plasma rotation with good temporal and spatial resolutions. A compact, new design for a high-throughput, tri-band high spectral resolution spectrometer has been developed for the charge-exchange recombination spectroscopy measurement on the HL-2A tokamak. The simultaneous measurements of He II (468.57 nm), C VI (529.1 nm), and Dα (656.1 nm accompanied by beam emission spectra) with an acquisition frequency up to 400 Hz are achieved by vertically binning the spectrum from each fiber in experiments. Initial results indicate that the system can provide radial profiles not only of ion temperature and rotation velocity, but also concentration of carbon. For the case of helium, the measurements for the ion temperature and rotation velocity are straightforward but the apparent concentration associated with the observed CX intensity is obviously too high. Modeling of the active He II CX feature including plume contributions needs to be carried out to extract the true helium concentration. The spectrometer could become a prototype for the ITER charge-exchange recombination spectroscopy diagnostic and the pilot experiments, as presented here, demonstrate the possibility of impurity concentrations measurements based on the combined measurement of local beam emission and charge-exchange recombination spectroscopy spectra.

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Measurement of Absolute Carbon Ion Density Profile Based on CXRS Diagnostic on HL-2A Tokamak

Cited by 2 publications

References 14 publications

Observation and Simulation of n = 1 Reversed Shear Alfvén Eigenmode on the HL-2A Tokamak

Observation and Simulation of n = 1 Reversed Shear Alfvén Eigenmode on the HL-2A Tokamak

The tri-band high spectral resolution spectrometer with gratings in tandem for the charge-exchange recombination spectroscopy diagnostic system on HL-2A tokamak

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