Application of the VUV and the soft x-ray systems on JET for the study of intrinsic impurity behavior in neon seeded hybrid discharges

Krawczyk, N.; Czarnecka, A.; Ivanova‐Stanik, I.; Zagórski, R.; Challis, C.; Frigione, D.; Giroud, C.; Graves, J. P.; Mantsinen, M.; Silburn, S.; Contributors, Jet

doi:10.1063/1.5038930

Cited by 8 publications

(4 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The experimental study of the W concentration in the JET ILW configuration is based on the deconvolution of signals from the soft x-ray (SXR)-cameras [19], using the approach described in detail in Ref [20,21]. It is assumed that the main radiator of soft x-rays is W, while the radiation from other metallic impurities is negligible.…”

Section: Resultsmentioning

confidence: 99%

Influences of heating and plasma density on impurity production and transport during the ramp-down phase of JET ILW discharge

Ivanova‐Stanik¹,

Zagórski²,

Chomiczewska³

et al. 2021

Plasma Phys. Control. Fusion

Self Cite

View full text Add to dashboard Cite

The aim of this paper is to study the influences of plasma heating and plasma density on impurity production and transport during the plasma-termination phase. We have analyzed the ramp-down (RD) phase of a set of representative high-current JET ITER-like wall discharges: #92 437 (disrupted) and #92 442 (soft landing), characterized by a high plasma current of I p = 3.5MA. Analysis is performed for different time slots within the RD phase, corresponding to different levels of electron line density and auxiliary heating power. Since the deuterium gas fluxes are different, the influence of the separatrix density is also analyzed. The main conclusion from the simulations is the observation that for the same average-electron density, a decrease of the separatrix density leads to an increase of the plasma temperature at the divertor plate, leading to increased W production and consequently to a larger W concentration and radiation in the core. When the central electron temperature approaches the 2 keV level, corresponding to the maximum W and Ni cooling rate, the radiation in the plasma’s center is enhanced. Ni radiation is more important in the RD phase.

show abstract

Section: Resultsmentioning

confidence: 99%

Influences of heating and plasma density on impurity production and transport during the ramp-down phase of JET ILW discharge

Ivanova‐Stanik¹,

Zagórski²,

Chomiczewska³

et al. 2021

Plasma Phys. Control. Fusion

Self Cite

View full text Add to dashboard Cite

show abstract

“…In such simulation, the W source was used as an input parameter [10]. The numerical analysis with COREDIV code of intrinsic impurity behaviour in neon seeded hybrid discharges with plasma parameters such as the plasma current (I p ), magnetic field (B T ), and NBI were kept the same at 1.4 MA, 1.9 T, and 16.3 MW, respectively are reported in reference [11].…”

Section: Introductionmentioning

confidence: 99%

Influence of the impurities in the hybrid discharges with high power in JET ILW

Ivanova‐Stanik¹,

Challis²,

Chomiczewska³

et al. 2022

Nucl. Fusion

Self Cite

View full text Add to dashboard Cite

The aim of this paper is to numerically study the influences of the impurities on the high power hybrid discharges in the JET ITER-like wall (ILW) configuration in the DD and deuterium–tritium (DT) scenarios. Numerical simulations with the COREDIV code of hybrid discharges with 32 MW auxiliary heating, 2.2 MA plasma current and 2.8 T toroidal magnetic field in the ILW corner configuration are presented. In the simulations five impurity species are used: intrinsic: beryllium (Be) and nickel (Ni) from the side walls, helium (He) from DT reaction, tungsten (W) from divertor and extrinsic neon (Ne) or argon (Ar) by gas puff. The extrapolation of the DD discharges to DT plasmas at the original input power of 32 MW and taking into account only the thermal component of the alpha-power, does not show any significant difference regarding the power to the target with respect to the DD case. Simulations show that sputtering due to D and T is negligible. In contrast, the simulations at auxiliary heating 39 MW show that the power to the target is possibly too high to be sustained for about 5 s by strike-point sweeping alone without any control by Ne seeding. The tungsten is produced mainly by Ni, Be and seeded impurities.

show abstract

“…Measurement of the Ni concentrations (c_Ni) in the plasmas were determined by the method described in detail in [36]. However, the quantitative measurement and comparison of W concentration was not possible due to disconnections of the SXR and XUV diagnostics, to protect them from damage when working with T. Such diagnostics were routinely used in previous studies [7,8,37,38], before the first T injection. The VUV SPRED spectrometer records, within the wavelength range of 147-213 Å, the W feature characterized by multiple overlapping unresolved transition arrays of W-ions ranging from W 14+ to W 35+ .…”

Section: Isotopic Dependency Of the Plasma Radiation Core High- And M...mentioning

confidence: 99%

ICRH-related impurity source and control across experiments in H, D, T plasmas at JET-ILW

Chomiczewska,

Gromelski,

Ivanova-Stanik

et al. 2024

Nucl. Fusion

Self Cite

View full text Add to dashboard Cite

The experimental and theoretical analysis were focused on experiments conducted to assess the effect of plasma isotopes, protium (H), deuterium (D), and tritium (T) on Ion Cyclotron Resonance Heating (ICRH) related plasma wall interactions (PWI). Comparison of L-mode discharges with N=1 3He and N=1 H minority ICRH heating scenarios were done for different isotopes. For the selected pulses, the behaviour of high-Z, mid-Z and low-Z intrinsic impurity and radiated power behaviour was investigated based on data from VUV, visible spectroscopy, and bolometry diagnostic at JET. It was found that for N=1 3He scenario during radiofrequency (RF) antennas operation, core W, Ni content, Be source and the radiated power are higher for /2 in comparison to dipole antenna phasing. Lowest core Ni, W content and radiated power is clearly observed for H plasmas in comparison to D and T, where for this ICRH scenario behaviour was similar. However, lower Be photon flux is observed for T in comparison to D plasmas. Be sputtering by He particles is responsible for such an effect. Additionally, several computer simulations were conducted using the COREDIV code. The difference in the electron temperature was due to the difference in the isotope masses. Increased temperature in the central plasma in the case of T plasmas leads to higherradiation in the central plasma in comparison to H plasmas. As a result, the power across separatrix is lower and the temperature on the divertor plate decreases with the increase of the isotope mass. At these temperatures on the divertor plate, W is not sputtered by the main plasma ions H, D and T and by He. For the N=1 H ICRH scenario clear difference between D and T plasma was observed with higher metallic impurity content for T plasma in comparison to D. Impurity content in the plasmas is found to be sensitive to the power balance between the antenna straps. Its minimum is observed for the maximum of Pcen/Ptot. 

show abstract

Application of the VUV and the soft x-ray systems on JET for the study of intrinsic impurity behavior in neon seeded hybrid discharges

Cited by 8 publications

References 13 publications

Influences of heating and plasma density on impurity production and transport during the ramp-down phase of JET ILW discharge

Influences of heating and plasma density on impurity production and transport during the ramp-down phase of JET ILW discharge

Influence of the impurities in the hybrid discharges with high power in JET ILW

ICRH-related impurity source and control across experiments in H, D, T plasmas at JET-ILW

Contact Info

Product

Resources

About