Analysis of the plasma blob formation/transport and its effects on impurity transport in the scrape-off layer regions

2018 ◽  
Vol 58 (6-8) ◽  
pp. 505-510 ◽  
Author(s):  
T. Maeda ◽  
K. Tominaga ◽  
S. Yamoto ◽  
A. Hatayama ◽  
H. Hasegawa ◽  
...  
Keyword(s):  
Impurity Transport ◽  
Plasma Blob

scholarly journals Effects of the Plasma Blob Nonlinear Formation/Transport on Impurity Transport in the SOL Regions

2019 ◽  
Vol 14 (0) ◽  
pp. 3403133-3403133
Author(s):  
Tomoyuki MAEDA ◽  
Hiroki HASEGAWA ◽  
Seiji ISHIGURO ◽  
Kazuo HOSHINO ◽  
Akiyoshi HATAYAMA
Keyword(s):  
Impurity Transport ◽  
Plasma Blob

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

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
Germán Vogel ◽  
Hongming Zhang ◽  
Yongcai Shen ◽  
Shuyu Dai ◽  
Youwen Sun ◽  
...  
Keyword(s):  
Inner Core ◽  
Extreme Ultraviolet ◽  
Transport Coefficients ◽  
Three Dimensional ◽  
Line Emission ◽  
Core Region ◽  
Emission Mitigation ◽  
One Dimensional ◽  
Impurity Transport ◽  
Transport Code

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.

scholarly journals Trace impurity transport in multi-species plasmas with large particle fluxes

2021 ◽  
pp. 127284
Author(s):  
E. Litvinova Mitra ◽  
E.J. Kolmes ◽  
I.E. Ochs ◽  
M.E. Mlodik ◽  
T. Rubin ◽  
...  
Keyword(s):  
Large Particle ◽  
Trace Impurity ◽  
Impurity Transport ◽  
Particle Fluxes

scholarly journals Impurity Transport in Reversed Shear and ELMy H-Mode Plasmas of JT-60U

1999 ◽  
Vol 75 (8) ◽  
pp. 952-966 ◽  
Author(s):  
Hidenobu TAKENAGA ◽  
Akira SAKASAI ◽  
Yoshihiko KOIDE ◽  
Yoshiteru SAKAMOTO ◽  
Hirotaka KUBO ◽  
...  
Keyword(s):  
Impurity Transport ◽  
Reversed Shear

Influence of Neutral-Beam Injection on Impurity Transport in the ISX-BTokamak

1981 ◽  
Vol 47 (9) ◽  
pp. 649-652 ◽  
Author(s):  
R. C. Isler ◽  
L. E. Murray ◽  
S. Kasai ◽  
D. E. Arnurius ◽  
S. C. Bates ◽  
...  
Keyword(s):  
Neutral Beam Injection ◽  
Neutral Beam ◽  
Beam Injection ◽  
Impurity Transport

Method to deduce local impurity transport quantities from the evolution of tomographically reconstructed bolometer signals during tracer injection at TJ-II

2004 ◽  
Vol 75 (10) ◽  
pp. 4231-4233 ◽  
Author(s):  
B. Zurro ◽  
M. A. Ochando ◽  
A. Baciero ◽  
K. J. McCarthy ◽  
F. Medina ◽  
...  
Keyword(s):  
Tracer Injection ◽  
Impurity Transport

Effects of Convective Solute and Impurity Transport in Protein Crystal Growth

1998 ◽  
Vol 102 (26) ◽  
pp. 5208-5216 ◽  
Author(s):  
Peter G. Vekilov ◽  
Bill R. Thomas ◽  
Franz Rosenberger
Keyword(s):  
Crystal Growth ◽  
Protein Crystal ◽  
Impurity Transport ◽  
Protein Crystal Growth

Impurity leakage and radiative cooling in the first nitrogen and neon seeding study in the slot divertor at DIII-D

2021 ◽  
Author(s):  
Livia Casali ◽  
David Eldon ◽  
Adam G McLean ◽  
Tom H Osborne ◽  
Anthony W Leonard ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Mean Free Path ◽  
Flow Reversal ◽  
Momentum Balance ◽  
Ionization Source ◽  
Power Flux ◽  
Impurity Transport ◽  
Plasma Drifts ◽  
High Level ◽  
The Impact

Abstract A comparative study of nitrogen versus neon has been carried out to analyze the impact of the two radiative species on power dissipation, SOL impurity distribution, divertor and pedestal characteristics. The experimental results show that N remains compressed in the divertor, thereby providing high radiative losses without affecting the pedestal profiles and displacing carbon as dominant radiator. Neon, instead, radiates more upstream than N thus reducing the power flux through the separatrix leading to a reduced ELM frequency and compression in the divertor. A significant amount of neon is measured in the plasma core leading to a steeper density gradient. The different behaviour between the two impurities is confirmed by SOLPS-ITER modelling which for the first time at DIII-D includes multiple impurity species and a treatment of full drifts, currents and neutral-neutral collisions. The impurity transport in the SOL is studied in terms of the parallel momentum balance showing that N is mostly retained in the divertor whereas Ne leaks out consistent with its higher ionization potential and longer mean free path. This is also in agreement with the enrichment factor calculations which indicate lower divertor enrichment for neon. The strong ionization source characterizing the SAS divertor causes a reversal of the main ions and impurity flows. The flow reversal together with plasma drifts and the effect of the thermal force contribute significantly in the shift of the impurity stagnation point affecting impurity leakage. This work provides a demonstration of the impurity leakage mechanism in a closed divertor structure and the consequent impact on pedestal. Since carbon is an intrinsic radiator at DIII-D, in this paper we have also demonstrated the different role of carbon in the N vs Ne seeded cases both in the experiments and in the numerical modeling. Carbon contributes more when neon seeding is injected compared to when nitrogen is used. Finally, the results highlight the importance of accompanying experimental studies with numerical modelling of plasma flows, drifts and ionization profile to determine the details of the SOL impurity transport as the latter may vary with changes in divertor regime and geometry. In the cases presented here, plasma drifts and flow reversal caused by high level of closure in the slot upper divertor at DIII-D play an important role in the underlined mechanism.

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