2,123 research outputs found
SOLPS-ITER modeling of divertor scenarios for EU-DEMO
No full textWe developed a first single null divertor scenario for EU-DEMO with the SOLPS-ITER code, including all charge states of D, He and Ar in the simulation and kinetic analysis of the neutral gas, but still leaving out drifts. Our results suggest that a partially detached divertor condition can indeed be obtained, with a corresponding peak heat flux on targets to ≈2 MW m-2, within the expected tolerable steady-state limits. The plasma re-attaches ≈30 cm (measured along the plate) from the low field side strike point deep in the SOL, with a consequent raise in the electron temperature up to ≈16 eV outside the detached region, which requires further analysis to assess a possible role of sputtering, especially considering W self-sputtering. The plasma we developed exhibits Z eff ≈ 1.9 in the core, and a pumping speed a few hundred's m3 s-1 to maintain steady-state; this points to the need of further studies to better characterize the He accumulation in the core region
Bloom (Benjamin), Engelbort (Max, D.), Hil Walker (H.), Fürst (Edward), Krat- wohl (David. R.), taxonomie : vol. 1
No full textDe Coster Sylvain. Bloom (Benjamin), Engelbort (Max, D.), Hil Walker (H.), Fürst (Edward), Krat- wohl (David. R.), taxonomie : vol. 1. In: Revue belge de philologie et d'histoire, tome 51, fasc. 3, 1973. Langues et littératures modernes - Moderne taal- en letterkunde. p. 732
Study of innershell photo-ionization-pumped L23M1 transition in Ca for the development of femtosecond X-ray laser
No full textA new physical scheme for femtosecond X-ray lasers, where the upper lasing is pumped by X-ray photons and the lower lasing level is depopulated via a Coster-Kronig radiationless transition, is analyzed for Ca. The transition wavelength is 4.1 nm, which is inside the water window. The peak spectral brightness of the X-ray laser output at 4.1 nm is predicted to be as large as 5 x 10(25) photons/sec./(mm(2) mrad(2) 0.1% bandwidth), which is 4 to 5 orders of magnitude brighter than a typical undulator radiation in the similar spectral region. In addition to the high flux, the expected duration of X-ray lasing of similar to 3 fs. will be useful for the study of fast dynamics in physical and biological sciences.open11sciescopu
Efficacité biologique relative (EBR) des neutrons produits à partir de deutons de 50 MeV et de protons de 34, 45, 65 et 75 MeV
No full textRBE of p(34) + Be, p(45) + Be, p(65), + Be, p(75) + Be and d(50) + Be neutron beams produced at the cyclotron "Cyclone" of Louvain-la-Neuve were measured. The biological criterion was the regeneration of the crypts of the intestinal mucosa (50 regenerated crypts per circumference) after abdominal irradiation in mice. Taking the p(65) + Be neutrons as reference, RBE values were found equal to 1.12, 1.07, 1.00 (Ref.), 0.96 and 1.02 respectively. These results are consistent with those published for cell lethality in vitro. However, the RBE variation is smaller than this previously obtained in the laboratory for growth inhibition in Vicia faba
On Kinetic Effects during Parallel Transport in the SOL
No full text1D kinetic (PIC) and fluid simulations have been performed in order to study boundary conditions and heat flux and viscosity limiting coefficients in the inter-ELM and ELMy SOLs. Simulated plasma parameters correspond to the JET SOL under different conditions. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
2s-photoionisation of atomic magnesium: Shake processes and Coster-Kronig radiationless decay
No full text2s-photoionization of magnesium is analyzed for incident energies
ranging up to three times the 2s threshold (96.6 eV). The 3s shake processes
amount to almost 30% of single photoionization. The shake-up
cross section exceeds 14% of the single one, and the
conjugate shake-up probability plays an important role in the energy range up
to three times the 2s
threshold.
The 2s2p63s2 Auger and
Coster-Kronig rates are calculated, and the 2s22p53s 1P
exit is found to be favoured (80% of the total decay), giving rise to the
line MgIII 231.73 Å
Preliminary analysis of the efficiency of non-standard divertor configurations in DEMO
No full textThe standard Single Null (SN) divertor is currently expected to be installed in DEMO. However, a number of alternative configurations are being evaluated in parallel as backup solutions, in case the standard divertor does not extrapolate successfully from ITER to a fusion power plant. We used the SOLPS code to produce a preliminary analysis of two such configurations, the X-Divertor (XD) and the Super X-Divertor (SX), and compare them to the SN solution. Considering the nominal power flowing into the SOL (PSOL = 150 MW), we estimated the amplitude of the acceptable DEMO operational space. The acceptability criterion was chosen as plasma temperature at the target lower than 5 eV, providing low sputtering and at least partial detachment, while the operational space was defined in terms of the electron density at the outboard mid-plane separatrix and of the seeded impurity (Ar only in the present study) concentration. It was found that both the XD and the SXD extend the DEMO operational space, although the advantages detected so far are not dramatic. The most promising configuration seems to be the XD, which can produce acceptable target temperatures at moderate outboard mid-plane electron density ( m−3) and Zeff= 1.3
Self-consistent coupling of DSMC method and SOLPS code for modeling tokamak particle exhaust
No full textIn this work, an investigation of the neutral gas flow in the JET sub-divertor area is presented, with respect to the interaction between the plasma side and the pumping side. The edge plasma side is simulated with the SOLPS code, while the sub-divertor area is modeled by means of the direct simulation Monte Carlo (DSMC) method, which in the last few years has proved well able to describe rarefied, collisional flows in tokamak sub-divertor structures. Four different plasma scenarios have been selected, and for each of them a user-defined, iterative procedure between SOLPS and DSMC has been established, using the neutral flux as the key communication term between the two codes. The goal is to understand and quantify the mutual influence between the two regions in a self-consistent manner, that is to say, how the particle exhaust pumping system controls the upstream plasma conditions. Parametric studies of the flow conditions in the sub-divertor, including additional flow outlets and variations of the cryopump capture coefficient, have been performed as well, in order to understand their overall impact on the flow field. The DSMC analyses resulted in the calculation of both the macroscopic quantities—i.e. temperature, number density and pressure—and the recirculation fluxes towards the plasma chamber. The consistent values for the recirculation rates were found to be smaller than those according to the initial standard assumption made by SOLPS
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