New linear plasma devices in the trilateral euregio cluster for an integrated approach to plasma surface interactions in fusion reactors

New linear plasma devices are currently being constructed or planned in the Trilateral Euregio Cluster (TEC) to meet the challenges with respect to plasma surface interactions in DEMO and ITER: i) MAGNUM-PSI (FOM), a high particle and power flux device with super-conducting magnetic field coils which will reach ITER-like divertor conditions at high magnetic field, ii) the newly proposed linear plasma device JULE-PSI (FZJ), which will allow to expose toxic and neutron activated target samples to ITER-like fluences and ion energies including in vacuo analysis of neutron activated samples, and iii) the plasmatron VISION I. a compact plasma device which will be operated inside the tritium lab at SCK-CEN Mol, capable to investigate tritium plasmas and moderately activated wall materials. This contribution shows the capabilities of the new devices and their forerunner experiments (Pilot-PSI at FOM and PSI-2 Julich at FZJ) in view of the main objectives of the new TEC program on plasma surface interactions. (C) 2011 Forschungszentrum Julich, Institut fur Energieforschung-Plasmaphysik. Published by Elsevier B.V. All rights reserved

Comparative population genetic structure of the endangered southern brown bandicoot, Isoodon obesulus, in fragmented landscapes of Southern Australia

Genetic connectivity is a key factor for maintaining the persistence of populations in fragmented landscapes. In highly modified landscapes such us peri-urban areas, organisms' dispersal among fragmented habitat patches can be reduced due to the surrounding matrix, leading to subsequent decreased gene flow and increased potential extinction risk in isolated sub-populations. However, few studies have compared within species how dispersal/gene flow varies between regions and among different forms of matrix that might be encountered. In the current study, we investigated gene flow and dispersal in an endangered marsupial, the southern brown bandicoot (Isoodon obesulus) in a heavily modified peri-urban landscape in South Australia, Australia. We used 14 microsatellite markers to genotype 254 individuals which were sampled from 15 sites. Analyses revealed significant genetic structure. Our analyses also indicated that dispersal was mostly limited to neighbouring sites. Comparisons of these results with analyses of a different population of the same species revealed that gene flow/dispersal was more limited in this peri-urban landscape than in a pine plantation landscape approximately 400 km to the south-east. These findings increase our understanding of how the nature of fragmentation can lead to profound differences in levels of genetic connectivity among populations of the same species.You Li, Steven J.B. Cooper, Melanie L. Lancaster, Jasmin G. Packer, Susan M. Carthe

Long term high resolution heavy metal leaching from soils to surface waters in a Dutch catchment

The impact of seasonal variation and drainage conditions on the leaching of cadmium and zinc was investigated by the application of a distributed pseudo 2D-model to the Keersop catchment in the south of The Netherlands. Soils in the area have been contaminated with heavy metals from zinc smelters during the period 1890 - 1973. Measurements indicated that these metals accumulate in the unsaturated upper part of the soils in the area. Metal concentrations in surface waters that drain the area were also elevated. A dynamic modelling approach for the soil system was applied to analyse the impact of temporal variations in weather on accumulation and transport of metals in the unsaturated zone, groundwater and in the drained water that leaches towards surface waters. The 1D SWAP model (www.swap.alterral.nl) was extended to enable the simulation of the drained discharge of heavy metals. The modelling approach included daily simulations for the period from 1890 - present. This allowed analysis of the dynamics of groundwater level fluctuations, drained water and metal discharge at the scale of a catchment. Both field and catchment monitoring were used to validate model results. The non-linear relation between discharge and solute transport of these high adsorbing substances was modelled using a high time resolution in the modelling approach and taking account for the groundwater level fluctuations to explain peak behaviour of the metal concentrations in surface waters

Electron cyclotron resonance heating on TEXTOR

The 110 GHz and the new 140 GHz gyrotron systems for electron cyclotron resonance heating (ECRH) and ECCD on TEXTOR are described and results of ECRH experiments with the 110 GHz system are reported. Central ECRH on Ohmic plasmas shows the presence of an internal electron transport barrier near q = 1. This is confirmed by modulated ECRH experiments. A central barrier is also indicated by ECRH in radiatively improved (RI) mode discharges and up to two barriers are seen with ECRH during the current ramp phase. ECRH control of sawteeth is reported for both Ohmic and RI mode target plasmas

Development of the 140 GHz gyrotron and its subsystems for ECH and ECCD in TEXTOR

A 800 kW, 140 GHz gyrotron has been mounted on TEXTOR. Initial operation was limited by arcs in the transmission line, and by pulse length restrictions due to the expected limited power handling of the window and the launching mirror. Measurements of power absorption in the window and launching mirror, however, showed them to be capable of handling full power, 3 s pulses, while arcing could be prevented by absorption of stray radiation at strategic position in the transmission line. This resulted in the realisation of full power, 3 s pulses on the plasma. Further measures were taken to prevent gyrotron operation in wrong modes or under conditions of low absorption in the plasma. Future improvements, expected to allow further extension of the pulse length to 10 s include: a CVD diamond window to replace the current quartz torus vacuum window, and a fast and accurate launcher. (c) 2005 Elsevier B.V. All rights reserved

Electron cyclotron resonance heating on TEXTOR

The 110 GHz and the new 140 GHz gyrotron systems for electron cyclotron resonance heating (ECRH) and ECCD on TEXTOR are described and results of ECRH experiments with the 110 GHz system are reported. Central ECRH on Ohmic plasmas shows the presence of an internal electron transport barrier near q = 1. This is confirmed by modulated ECRH experiments. A central barrier is also indicated by ECRH in radiatively improved (RI) mode discharges and up to two barriers are seen with ECRH during the current ramp phase. ECRH control of sawteeth is reported for both Ohmic and RI mode target plasmas