B2.5-Eunomia simulations of Pilot-PSI plasmas

Wieggers, R. C.; Coster, D.; Groen, P. W. C.; Blank, H. J. de; Goedheer, W. J.

doi:10.1016/j.jnucmat.2013.01.135

Cited by 21 publications

(32 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although no direct effects on the plasma can be modelled with Eunomia in the stand-alone version, important insights on the behaviour of neutral atoms and molecules, such as their sources, sinks, spatial distribution and transport, can be studied. Further specifications on the code, such as calculation of velocity distributions and temperatures, can be found in [11]. Figures 12 and 13, taken from [11], show a schematic view of the linear plasma machine Pilot-PSI and the derived cylindrical symmetry adopted in Eunomia.…”

Section: Wherementioning

confidence: 99%

“…Further specifications on the code, such as calculation of velocity distributions and temperatures, can be found in [11]. Figures 12 and 13, taken from [11], show a schematic view of the linear plasma machine Pilot-PSI and the derived cylindrical symmetry adopted in Eunomia. In the code, the simulation is carried out in a 3dimensional environment and the results are provided in a 2-D grid averaged over the rotation axis, as can be seen in figure 13.…”

Section: Wherementioning

confidence: 99%

“…The reduced set of chemical equations relevant for Magnum-PSI i.e. highdensity low-temperature plasma has been subsequently implemented in Eunomia [11], a spatially resolved Monte-Carlo code for the transport of neutrals originally developed for the Magnum-PSI [12] predecessor Pilot-PSI [13]. To study the influence of N 2 and related species on the recombination mechanisms, the density of atomic hydrogen has been traced for three different seeding cases.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Studying the influence of nitrogen seeding in a detached-like hydrogen plasma by means of numerical simulations

Perillo

Chandra

Akkermans

et al. 2018

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

The leading candidate for impurity seeding in ITER is currently nitrogen. To date, there are only a few studies on the plasma chemistry driven by N 2 /H 2 seeding and its effect on the molecular-activated recombination of incoming atomic hydrogen ions in a detached-like scenario. Numerical simulations are needed to provide insights into such mechanisms. The numerous amount of plasma chemical reactions that may occur in such an environment cannot be entirely included in a 2 or 3-dimensional code such as Eirene. A complete global plasma model, implemented with more than 100 plasma chemical equations and 20 species, has been set up on the basis of Plasimo code. This study shows two main nitrogen-included recombination reaction paths resulted to be dominant, i.e. the ion conversion of NH followed by dissociative recombination and a proton transfer between H 2 + and N 2 , producing N 2 H +. These two processes are referred to as N-MAR (nitrogen-molecular activated recombination) and have subsequently been implemented into Eunomia, a spatially-resolved Monte Carlo code, designed to simulate the neutrals inventory in linear plasma machines such as Pilot-PSI and Magnum-PSI. To study the effect of N 2 on the overall recombination, three cases of study have been set up: from a defined puffing location with a constant total seeding rate of H 2 + N 2 , three N 2 ratios have been simulated, i.e. 0, 5 and 10%. The parameter monitored is the density of atomic hydrogen, being the final hydrogenic product of any recombination mechanism in the scenario considered. The difference in H density between the 0% case and the 10% case is about a factor 3. The importance of NH as electron donor is highlighted and N-MARs confirmed as reaction routes enhancing the conversion of ions to neutrals, making the heat loads to the divertor plate more tolerable. This work is a further step towards the full understanding of the role of N 2-H 2 molecules in a detached divertor plasma.

show abstract

Section: Wherementioning

confidence: 99%

Section: Wherementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Studying the influence of nitrogen seeding in a detached-like hydrogen plasma by means of numerical simulations

Perillo

Chandra

Akkermans

et al. 2018

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

show abstract

“…The plasma potential is not precisely known [23,24] but is only a few eV. The ion energy is therefore dominated by the target bias and close to 40 eV.…”

Section: Deuterium Plasma Exposurementioning

confidence: 99%

“…The partially detached plasma in the divertor region are expected to have a high electron density (10 20 -10 21 m −3 ) and electron temperatures of 1 -10 eV [2,3]. This leads to extremely intense particle and heat flux densities on the divertor of ∼10 24 ions m −2 s −1 and ∼10 MW m −2 , respectively. Its high thermal conductivity and melting point as well as its low erosion rate make tungsten favourable over many other materials.…”

Section: Introductionmentioning

confidence: 99%

Surface morphology and deuterium retention of tungsten after low- and high-flux deuterium plasma exposure

Hoen¹,

Balden²,

Manhard³

et al. 2014

Nucl. Fusion

View full text Add to dashboard Cite

Abstract.The surface morphology and deuterium retention were investigated of polycrystalline tungsten targets that were exposed to deuterium plasmas at widely varying conditions. By changing only one parameter at a time, the isolated effects of flux, time and pre-damaging on surface modifications and deuterium retention were studied. The sample exposed to low-flux plasma (10 20 m −2 s −1 ) is mostly smooth with only a few areas containing very large blisters (50 -500 µm). The samples exposed to high-flux plasmas (10 24 m −2 s −1 ) show large numbers of smaller blisters (1 -10 µm) and in addition even smaller protrusions (<750 nm). The size of the blisters and their density strongly increase with fluence. Pre-damaging tungsten with MeV ions leads to less blisters but to more protrusions. In addition to these (sub-)micrometer-sized structures, all samples show formation of nanostructures. Comparison of a low-flux and high-flux sample exposed to similar fluence showed that the variation in morphology is dominated by the flux differences. It is shown that the blisters and protrusions originate in inter-and intra-granular cavities, respectively. The depth of the cavities underneath the surface correlates well with the depth distributions of the retained deuterium. Trapping of significant amounts of deuterium therefore seems to take place in and/or close to these cavities and gives rise to an additional peak in the thermal desorption spectrum at 700 K.PACS numbers: 28.52.Fa, 28.52. Nh, 52.40.Hf, 52.77.Dq, 61.80.Jh, Submitted to: Nuclear Fusion Surface morphology and deuterium retention at high-flux deuterium plasmas 2

show abstract