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The latest version of the SONIC code with the extended thermal force model that is capable to treat collisionality dependence of the force has been applied to the interpretative simulation of L‐mode discharge of JT‐60 U to investigate the impact of kinetic correction of the thermal force on the scrape‐off layer (SOL) plasma properties. As a first attempt, we have selected an L‐mode attached discharge #39090 (Ip = 1.6 MA, Bt = 3.1 T, and PNBI = 4.5 MW), where n‾e$$ {\overline{n}}_e $$ = 2.08 × 1019 m−3, n‾e/nGr$$ {\overline{n}}_e/{n}_{Gr} $$ = 0.392 with deuterium plasmas. It has been found that the peak values of SOL impurity density are reduced by a factor of 2, with the kinetic correction, because the thermal force is reduced by the low collisionality of SOL plasma between the X‐point and the (inner and outer) midplane. On the other hand, the profiles near the divertor plates are unaffected by the kinetic correction due to the highly collisional condition. The kinetic correction is found more pronounced for the higher charge states impurity due to the charge dependence of the parallel impurity force balance. Overall effects due to the kinetic correction on the total impurity radiation and the divertor heat load are confirmed to be a few % in the present discharge condition of JT‐60U. [ABSTRACT FROM AUTHOR]

The SOLPS‐ITER3.0.8 code with new Grad‐Zhdanov module was applied for predictive modeling of tritium plasma and deuterium‐tritium mixture in tokamak JET. The moderate power scenario of shot JPN #85278 modeled earlier for deuterium plasma was taken as a starting point. Effect of puffing increase, which was applied in experiment, on divertor conditions and inter‐ELM tungsten sputtering for both working gases and on isotope separation in their mixture is analyzed. Both for attached and for semi‐detached outer targets, the tritium plasma shows moderate increase in SOL width compared to deuterium one. The tungsten sputtering at the outer target in the inter‐ELM period for tritium is an order of magnitude bigger than that for deuterium. The D–T separation in the D–T mixture is moderate. [ABSTRACT FROM AUTHOR]

The hydrogenic two‐point model (H‐2PM), an analytical model for the scrape‐off layer that predicts a common electron and ion temperature and density along a flux tube from a target temperature and density, is adapted to a single‐species helium (He) model, preserving the 2PM assumptions and analytical nature. Across a range of densities and heating powers, the predicted Te$$ {T}_e $$ is within 20eV$$ 20\kern0.3em \mathrm{eV} $$ of upstream measurements by high‐resolution Thomson scattering (HRTS) for low‐confinement He plasmas performed in JET ITER‐like wall (JET‐ILW). For high‐recycling conditions, He‐2PM predictions of ne$$ {n}_e $$ were within 10% of the Li‐beam diagnostic measurements, excluding the near‐SOL, when assuming Zeff=1$$ {Z}_{\mathrm{eff}}=1 $$, suggesting the divertor SOL was not fully ionised in the JET‐ILW He plasmas. [ABSTRACT FROM AUTHOR]

The evaluation of activities from radionuclides inside a vacuum vessel is required for the safe maintenance and estimation of the activation level of fusion devices. The Large Helical Device (LHD), Toki, Japan, has been performing deuterium plasma experiments since 2017, and radionuclides have accumulated in components such as vacuum vessels. In this work, the gamma-ray spectrum and activity of each detected radionuclide in an LHD vacuum vessel were evaluated using portable high-purity germanium (P-HPGe) and numerical calculations of photon transport for comparison with the removed armor tiles to evaluate the occupational exposure in the maintenance of LHD experiments. Measurements using the P-HPGe detector were performed at 20 positions along the toroidal direction of the LHD, at each O port, and between each pair of adjacent O ports. Using the estimated efficiency of the photoelectronic effects inside the P-HPGe detector calculated by Monte Carlo N-particle code version 6.1, the activities of the radionuclides in the armor tiles attached to the vacuum vessel were evaluated. The estimated activity concentrations were compared with the measured activities of the armor tiles removed from the vacuum vessel. Gamma rays from 58Co, 54Mn, and 60Co were detected, and the measured activities of 58Co and 54Mn generated by fast neutrons in the armor tile were almost consistent with those obtained from the removed armor tiles. The radioactivity of 60Co in the armor tile was underestimated compared with the activity obtained from the removed armor tiles. The measurement of activation by fast neutrons is feasible, whereas activation by thermal neutrons requires more accurate calculations and surveys to be measured using this method. [ABSTRACT FROM AUTHOR]

The Monte‐Carlo code ERO2.0 uses full orbit resolution to follow impurity particles throughout the plasma volume to determine the local erosion and deposition fluxes on the plasma‐facing components of fusion devices in magnetic confinement fusion. To have direct comparisons to other transport codes (e.g., ASCOT and DIVIMP) and to accelerate the code, guiding centre approximation (GCA) was implemented into ERO2.0. In addition, a hybrid simulation mode for ERO2.0 was developed, in which the advantages of both full orbit resolution and guiding centre approximation are used. In typical scenarios in this simulation mode, full orbit resolution is applied exclusively near the wall region, while GCA is used everywhere else along a particle's trajectory. Special emphasis was put on the validation of the implementation by an inner‐code benchmarking to pure full orbit simulations. Analysed scenarios included test plasmas with simplified geometry and a realistic test case corresponding to a deuterium limiter plasma used in JET pulse #80319. The results of simulations performed in the hybrid simulation mode are in very good agreement to corresponding pure full orbit simulations, while a significant code speed‐up was achieved. [ABSTRACT FROM AUTHOR]

Fast ion confinement is of major importance for the ignition of a burning fusion plasma. In future deuterium plasma campaigns of the Wendelstein 7‐X stellarator, W7‐X, the amount of triton burn‐up is one possible measure for fast ion confinement. A well‐established technique to observe triton burn‐up is the 14 MeV neutron rate. In this paper, it is estimated whether an existing scintillating fibre neutron detector is also suited to measure triton burn‐up in W7‐X with sufficient accuracy. An estimation is presented, which can be applied to any tokamak or stellarator design and is one‐dimensional in the minor radius. The inputs are profiles of density, temperature, and differential volume element as well as the triton slowing‐down time. The estimation calculates the thermal deuteron fusion rate and the associated deuteron‐triton fusion rate; thus, the triton burn‐up generated 14 MeV neutron rate. It neither takes triton diffusion nor explicit losses into account. This thermally generated fusion rate is compared to the neutral beam injection heating induced beam‐plasma fusion rate. [ABSTRACT FROM AUTHOR]

Two sets of pure deuterium plasmas are simulated using UEDGE, one including atoms and molecules and the other including atoms only as separate fluid species. Simulation results in one and two dimensions are reported to assess the role of molecules in tokamak plasmas. It is shown that thermal coupling of the molecules to the plasma can be relevant for the onset of detachment under highly collisional conditions in simple geometries, but play a modest role at low collisionality. Ion‐molecule equipartition presents an additional ion energy loss channel, dissipating ion energy that would otherwise heat the electrons by equipartition. The resulting reduced electron temperature increases the ion‐electron recombination by an order of magnitude as the plasma density is increased, yielding earlier and deeper detachment. [ABSTRACT FROM AUTHOR]

In these proceedings, we show that time-dependent density functional theory is capable of stopping calculations at the extreme conditions of temperature and pressure seen in warm dense matter. The accuracy of the stopping curves tends to be up to about 20% lower than empirical models that are in use. However, TDDFT calculations are free from fitting parameters and assumptions about the model form of the dielectric function. This work allows the simulation of ion stopping in many materials that are difficult to study experimentally. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

In this paper the transport properties of non-isothermal dense deuterium-tritium plasmas were studied. Based on the effective interaction potentials between particles, the Coulomb logarithm for a two-temperature nonisothermal dense plasma was obtained. These potentials take into consideration long-range multi-particle screening effects and short-range quantum-mechanical effects in two-temperature plasmas. Transport processes in such plasmas were studied using the Coulomb logarithm. The obtained results were compared with the theoretical works of other authors and with the results of molecular dynamics simulations. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]