Enhancement of edge impurity transport with ECRH in the HL-2A tokamak

Cui, Z.Y.; Morita, S.; Zhou, H.Y.; Ding, X.T.; Sun, Peng; Kobayashi, M.; Cui, Xihong; Xu, Yuan; Huang, Xianli; Shi, Z.B.; Cheng, J.; Li, Y.G.; Feng, B.B.; Song, Shaodong; Yan, L.W.; Yang, Qingwei; Duan, X.R.

doi:10.1088/0029-5515/53/9/093001

Cited by 34 publications

(33 citation statements)

References 35 publications

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“…In contrast, the temperature gradient of the main ions has stabilizing and destabilizing effects in the regions of R/L nz <130 and R/L nz >130, respectively, and, therefore, raises the threshold in NIDG case (see the light blue curve for 0.2 i h = versus the red curve for 0 i h = in figure 19(c) Considering the parameters R/L nz = 25 and f z =0.3, such a reversion occurs at R/L nz >83. Nevertheless, more numerical results demonstrate that such a reversion is not necessary for the instability to occur, although reversed profiles of main ions have been observed in the periphery of HL-2A, TJ-II and RFXmod plasmas [28,32,50,51].…”

Section: Impurity Modementioning

confidence: 94%

Kinetic micro-instabilities in the presence of impurities in toroidal magnetized plasmas

Dong¹

2018

Plasma Sci. Technol.

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The theoretical and numerical studies on kinetic micro-instabilities, including ion temperature gradient (ITG) driven modes, trapped electron modes (TEMs) in the presence of impurity ions as well as impurity modes (IMs), induced by impurity density gradient alone, in toroidal magnetized plasmas, such as tokamak and reversed-field pinch (RFP) are reviewed briefly. The basic theory for IMs, the electrostatic instabilities in tokamak and RFP plasmas are discussed. The observations of hybrid and coexistence of the instabilities are categorized systematically. The effects of impurity ions on electromagnetic instabilities such as ITG modes, the kinetic ballooning modes (KBMs) and kinetic shear Alfvén modes induced by impurity ions in tokamak plasmas of finite β (=plasma pressure/magnetic pressure) are analyzed. The interesting topics for future investigation are suggested.

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Section: Impurity Modementioning

confidence: 94%

Kinetic micro-instabilities in the presence of impurities in toroidal magnetized plasmas

Dong¹

2018

Plasma Sci. Technol.

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“…The independent transport coefficients can be obtained when more than three successive lines are used to compare with simulated results. In a similar study of ECRH effects on carbon at HL-2A (Cui et al 2013), the same method showed that as few as two successive emission lines are needed to determine ν and D if additional constraints are taken into account on the radial profiles and impurity sources.…”

Section: One-dimensional Modelling With Strahlmentioning

confidence: 99%

Experimental and simulation study of impurity transport response to RMPs in RF-heated H-mode plasmas at EAST

et al. 2021

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Spatial profiles of impurity emission measurements in the extreme ultraviolet (EUV) spectroscopic range in radiofrequency (RF)-heated discharges are combined with one-dimensional and three-dimensional transport simulations to study the effects of resonant magnetic perturbations (RMPs) on core impurity accumulation at EAST. The amount of impurity line emission mitigation by RMPs appears to be correlated with the ion Z for lithium, carbon, iron and tungsten monitored, i.e. stronger suppression of accumulation for heavier ions. The targeted effect on the most detrimental high-Z impurities suggests a possible advantage using RMPs for impurity control. Profiles of transport coefficients are calculated with the STRAHL one-dimensional impurity transport code, keeping $\nu /D$ fixed and using the measured spatial profiles of $\textrm{F}{\textrm{e}^{20 + }}$ , $\textrm{F}{\textrm{e}^{21 + }}$ and $\textrm{F}{\textrm{e}^{22 + }}$ to disentangle the transport coefficients. The iron diffusion coefficient ${D_{\textrm{Fe}}}$ increases from $1.0- 2.0\;{\textrm{m}^2}\;{\textrm{s}^{ - 1}}$ to $1.5- 3.0\;{\textrm{m}^2}\;{\textrm{s}^{ - 1}}$ from the core region to the edge region $(\rho \gt 0.5)$ after the onset of RMPs. Meanwhile, an inward pinch of iron convective velocity ${\nu _{\textrm{Fe}}}$ decreases in magnitude in the inner core region and increases significantly in the outer confined region, simultaneously contributing to preserving centrally peaked $\textrm{Fe}$ profiles and exhausting the impurities. The ${D_{\textrm{Fe}}}$ and ${\nu _{\textrm{Fe}}}$ variations lead to reduced impurity contents in the plasma. The three-dimensional edge impurity transport code EMC3-EIRENE was also applied for a case of RMP-mitigated high-Z accumulation at EAST and compared to that of low-Z carbon. The exhaust of ${\textrm{C}^{6 + }}$ toward the scrape-off layer accompanying an overall suppression of heavier ${\textrm{W}^{30 + }}$ is observed when using RMPs.

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“…Core impurity transport in the outer half of the plasma radius is studied in low-density ECH discharges (2 × 10 13 cm −3 ) of HL-2A [38]. A ratio of CV to CIV indicating an index of the core impurity transport between LCFS (last closed flux surface) and a radial region of the CV emission, e.g.…”

Section: Core Impurity Transportmentioning

confidence: 99%