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H-mode operation in the low-shear stellarator W7-AS is achieved for specific plasma edge topologies characterized by three `operational windows' of the edge rotational transform. An explanation for this strong influence of the magnetic configuration could be the increase of viscous damping if rational surfaces and thus island structures occur withinthe relevant plasma edge layer, thereby impeding the development of an edge transport barrier. Prior to the final transition to a quiescent state, the plasma edge passes a rich phenomenology of dynamic behaviour such as dithering and ELMs. Plasma edge parameters indicate that a quiescent H-mode occurs if a certain edge pressure is achieved.

A low density H-mode plasma has been selected for detailed inter-ELM modelling by the SOLPS code package, with the coupled treatment of its plasma (fluid code B2) and neutral (Monte-Carlo code Eirene) parts. Good quality measured midplane density and temperature profiles, covering the pedestal region and stretching far into the SOL, as well as several other parameters and profiles measured in the divertor, have enabled testing the consistency of code solutions with experiment. Once the upstream, midplane profiles have been fitted, and the global parameters (e.g. input power into the computational grid, radiated power) matched, the code reproduces experimental profiles and control parameters in the divertor with an accuracy within a factor of 2. Deviations of modelled parameters from the experiment were found around the strike point position where most of the power was deposited on the target. The deviations are consistent among themselves and all point to one common problem with the modelling: the predicted divertor electron temperature is too low and the density too high, compared with the experiment. The largest inconsistency between the code and experiment was in the magnitude of the peak H?radiation in the outer divertor, which was larger by a factor of 2 in the code simulations. In addition, the code predicts a somewhat higher sub-divertor neutral flux but lower carbon impurity content in the edge plasma than in the experiment, as well as lower CIII emission. The discrepancy between H?profiles can to a large degree be attributed to profile effects: the simulated H?emission profiles are narrower than in the experiment, reflecting the tendency of the neutral-plasma mix to congregate excessively around the strike point in the modelling. At the same time, the integrated H?emission matches very well with the experiment.

At certain values of the edge rotational transform &bariota;_a, the confinement quality of plasmas in the Wendelstein 7-AS (W7-AS) stellarator is found to react very sensitively to small modifications of the edge rotational transform &bariota;_a. As &bariota;_a can be reproducibly changed either by external fields or by a small plasma current, these transitions offer a precise way to systematically analyse differences in plasma turbulence between bad and good confinement cases. This paper presents results of the study of electron density fluctuations associated with confinement changes. Wavenumber and frequency spectra and radial profiles are compared. A slow and reproducible transition is induced by a small plasma current and the sequence of events leading to bad confinement is investigated. The laser scattering core plasma density fluctuation measurements are complemented by edge beam emission spectroscopy results and magnetic fluctuation measurements with Mirnov coils. Clear correspondence between plasma fluctuations and confinement degradation is observed: the weight of larger structures increases, fluctuations increase in the plasma core, the poloidal flow velocity decreases and regions of mode-like activity move radially in the plasma. These changes occur gradually and controllably if the magnetic configuration is steered by a small plasma current.

In this paper we describe impurity line emission measurements in the divertor of ASDEX Upgrade during high power neutral beam heated discharges. We focus on detached conditions where the dominating part of the radiation comes from the X-point region. Spatially resolved line emission in the VUV and visible spectral region of the intrinsic carbon and additionally puffed impurities (neon and nitrogen) is presented. A simple interpretation of the line emission profiles is given and they are also compared to the results of bolometry.

Abstract.: In a joint experiment the TAPS and CERES collaborations have studied the production of the neutral mesons and in 450 GeV p-Be and p-Au collisions at the CERN SPS. The mesons were identified by their , , and decay modes. The cross sections were measured down to very low ( 20 MeV/c) near mid-rapidity (). The and cross sections are smaller than expected from extrapolations of earlier data to low . Integrated over all , the ratios and / are lower by about 25% compared to previously published values. The reduction may be attributed to the large number of low pions from decays of heavier mesons. In addition, we have studied the dependence of neutral meson production on the mass of the nuclear target and find it in good agreement with previous measurements of charged mesons.

Activities of the lactate dehydrogenase within the periportal zone and within the perivenous zone in the first layer of hepatocytes adjacent to terminal hepatic venules and the remainder of the perivenous parenchyma of the liver acinus were measured using a Lowry technique during a full 24-h cycle (08.00-08.00) in untreated adult male Wistar rats kept under 12 h of light and 12 h of darkness, scotophase 18.25-06.25. In all three regions studied a broad first maximum was recorded between 10.00 and 22.00 with the peak value at 16.00 and a high and narrow peak at 24.00. Zonal and intrazonal heterogeneity of the lactate dehydrogenase were retained during the full day and night cycle. The regions displayed individual dynamic changes in enzyme activity.

Three methods that are adapted to the various consistencies of plants are as follows: 1. Samples are placed for 10-14 hr at 60° C in a 1% aqueous solution of basic fuchsin, to which 10 gm of solid NaOH per 100 ml are added. 2. Samples when taken out of 95% alcohol are placed in a 1% solution of basic fuchsin in 95% alcohol for 24 hr; after washing in water, they are placed in a 15% solution of NaOH at 60° C until cleared. 3. Samples are placed in a 15% aqueous solution of NaOH at 60° C until cleared, then for 24 hr at 60° C in 15% NaOH containing basic fuchsin. After being stained and cleared by one of these three methods, the samples are rinsed in water, dehydrated and then passed into a mixture of absolute alcohol and concentrated HC1 (3:1) for 1-15 min, rinsed in absolute alcohol, cleared in xylene and mounted in Canada balsam. The lignified tissues appear red; the others, transparent.