Search

Ne ion visible spectrum, which is consistent with spectra in VUV ranges, is calculated and synthesised for comparison with experimental spectrum. No spectral lines from highly charged Ne ions are identified but Ne III (Ne2+) ion is the highest charge which yields spectral lines in the visible range with sufficiently high intensity to be observed. Two-dimensional visible spectroscopic measurement of Ne III 4f-5g line and C IV 3s-3p line with an aid of computer tomography technique provides reconstructed emissivity distributions. Comparison of the emissivity distributions reveals that Ne III emissivity is peaked at the high field side of the X-point and C IV is distributed along the outer divertor leg in the case of inner divertor detachment, showing that Ne III contributes more to radiation around the X-point. In contrast, in the case of attachment, Ne III emissivity is peaked at the high field side of the X-point similarly in the detached case but with lower intensity while C IV emissivity is peaked at the X-point, contributing to the X-point radiation. However, given that the divertor plasma is attached, the cabon radiation is not sufficient for detachment onset. Keywords: Impurity, Radiation, Transport, Seeding

The time dependence of remanence coercivity and thermal stability were investigated for hard/soft-stacked media consisting of a magnetically hard granular layer underneath a very thin soft layer with a large saturation magnetization, M s . The values of remanence coercivity at measurement times t ′=10 3 and 10 −5 s (pulse field) were measured, and defined as H r and H r P . The remanence coercivity on the recording time scale, H r (1 ns), and the energy barrier, Δ E / kT , were evaluated by fitting H r and H r P to Sharrock's equation taking into account the power law variation of the energy barrier, n . The value of H r (1 ns) for a (Co–Pt)–SiO 2 (9 nm)/Co–SiO 2 (2 nm) stacked medium with an interfacial coupling control layer was about 9 kOe, which was less than half of that of a (Co–Pt)–SiO 2 (9 nm) conventional medium (=21.3 kOe). The value of Δ E / kT for the stacked medium was about 111 ( n =0.7), and was not significantly different from the conventional medium. Moreover, no significant difference in the rate of decrease of H r with increasing temperature was observed between media with and without interlayers. These results indicate that the use of a thin soft layer with high M s was effective at significantly reducing H r with no notable change in thermal stability.

The B2-EIRENE code has been compared with plasma edge measurements from Alcator C-MOD, DIII-D, JET, JT-60U in L-mode and H-mode regimes. Similarities in L-mode discharges between JET and JT-60U are well reproduced by the code as well as the sudden approach to detachment seen in JT-60U when a 1% chemical sputtering yield for carbon is assumed. Comparisons between similar L-mode regimes in JET, JT-60U and Alcator C-MOD reveal the larger importance of anomalous energy convection in Alcator C-MOD with regard to larger tokamaks. H-mode discharges of DIII-D and JET can be satisfactorily modelled with similar values of the transport coefficients (approximately an order magnitude smaller than in L-mode) when the power flow into the scrape-off layer (SOL) is dominated by the ion channel, as previous EDGE2D simulations for JET suggested.