Impurity Emission Behavior in the Soft X-Ray and Extreme Ultraviolet Range on EAST

Shen, Yuquan; Lyu, Bo; Du, Xuewei

doi:10.1088/1009-0630/17/3/02

Cited by 8 publications

(4 citation statements)

References 32 publications

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“…It was surmised that other impurity lines might overlap with them, which would have an effect on the fitting results of ion and electron temperature. The W XLIV at 3.963 60 Å and W XLV at 3.973 00 Å diffracted by He-like crystal of the first order were identified on the side of the X and Y lines, respectively, since the upper divertors on EAST contain a large amount of tungsten [13], and the existence of these tungsten lines were most likely due to the ionization of tungsten at high electron temperatures, especially during the H-mode phase. It is also noted that the W XLVIII at 3.691 00 Å marked in red indicated that this line was diffracted by H-like crystal though it was located in He-like argon spectra.…”

Section: Analysis Of Impurity Linesmentioning

confidence: 98%

Measurement of impurity lines with two-crystal x-ray spectrometers on EAST

Yang

Chen

2018

Plasma Sci. Technol.

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To simultaneously measure the He-like and H-like argon spectra, a two-crystal assembly has been deployed to replace the previous single crystal on the tangential x-ray crystal spectrometer. By selecting appropriate crystals with similar Bragg angles, plasma temperature in the range of 0.5 keVT e 10 keV and rotation can be diagnosed based on the He-like and H-like argon spectra. However, due to the added complexity in the two-crystal assembly in which the spectra might be diffracted by two crystals, some additional impurity lines were identified. For example, tungsten (W) lines in different ionization states were diffracted by the He-like and H-like crystal. Additional molybdenum (Mo) lines in the wavelength range of He-like and H-like argon spectra lines were also summarized. The existence of these additional lines caused the fitted temperature to be different from the true values. This paper presents the identified lines through a comparison with available database, which should be included in the fitting procedure.

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Section: Analysis Of Impurity Linesmentioning

confidence: 98%

Measurement of impurity lines with two-crystal x-ray spectrometers on EAST

Yang

Chen

2018

Plasma Sci. Technol.

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“…In the MHD-free phase at 4.18 s (t1 in figure 6(a)), there are no MHD mode and no magnetic reconnection. The hollow distribution of SXR profiles in figure 6(b) is a result of plasma impurities [22]. The impurities lead to strong radiation loss in the core and then cause the precursor MHD mode of = m 2.…”

Section: Locations Of Fast Electron and Its Generationmentioning

confidence: 97%

Experimental study on fast electron generation during internal crash

Mai¹,

Hu²,

Xu³

et al. 2021

Plasma Sci. Technol.

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Hard x-ray (HXR) burst is found during internal crash in the flat top current stage of experimental advanced superconducting tokamak (EAST) discharges and it is caused by fast electrons. The generated electrons during internal crashes may be an operational safety issue in advanced tokamaks. During an internal crash, locations of fast electron generation from HXR evolution agree with areas of magnetic reconnection from soft x-ray (SXR) tomographic reconstruction. Further statistical analyses show a 27 μs time difference between SXR crashes and HXR bursts, and the agreement between time broadening of HXR bursts and estimated characteristic time of magnetic reconnection in EAST. The magnetic reconnections during internal crash are proved to generate fast electrons, by both spatial and temporal agreements.

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“…[2] Impurity accumulation is found to be more severe for heavier impurity species. [3] On the EAST tokamak, heavy impurity species are mainly from metal impurities such as iron, copper, molybdenum, and tungsten, [4] and impurity accumulation is often observed, especially during the high-density H-mode plasma operations.…”

Section: Introductionmentioning

confidence: 99%

Measurement of molybdenum ion density for L-mode and H-mode plasma discharges in the EAST tokamak*

Shen¹,

Zhang²,

Lyu³

et al. 2020

Chinese Phys. B

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We report the measurement of total molybdenum ion density for L-mode and H-mode plasmas on EAST using spectral lines observation and calculation based on an impurity transport code. A flat-filed extreme ultraviolet spectrometer with some spatial resolution is used to obtain the radial profiles of molybdenum spectral line emissions. The absolute calibration for the extreme ultraviolet spectrometer is finished by comparing the calculated bremsstrahlung intensity with the readings of CCD detector. Molybdenum ion transport study is performed using the radial ion density profiles and one-dimensional impurity transport code STRAHL. The total molybdenum density profiles are determined from the transport analysis. The molybdenum density during L-mode and H-mode phases are obtained, which are about 3 and 4 orders of magnitude smaller than the electron density, respectively. An inward pinch is found during the H-mode phase that leads to the peaked profile of molybdenum density.

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Impurity Emission Behavior in the Soft X-Ray and Extreme Ultraviolet Range on EAST

Cited by 8 publications

References 32 publications

Measurement of impurity lines with two-crystal x-ray spectrometers on EAST

Measurement of impurity lines with two-crystal x-ray spectrometers on EAST

Experimental study on fast electron generation during internal crash

Measurement of molybdenum ion density for L-mode and H-mode plasma discharges in the EAST tokamak*

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