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2010
The retention of deuterium fuel during MAST discharges has been studied using the method of global gas balance. The results show that with inter-shot 4 He- GDC, the total number of particles retained for a discharge increases with total number of injected particles, and the total retention fraction stays very high, mostly around 80%, and can be alm…
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2010
The surface or “skin” current that can flow at a perturbed interface between plasma and vacuum is considered in the approximation where a surface marks a sharp transition from plasma to vacuum. A short magnetohydrodynamic calculation gives an exact and general expression for the component perpendicular to the average of the magnetic field eithe…
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2008
Measurements have been made of the emittance plot of a partly neutralized positive ion beamlet, using a slit, a polymer target, and an infrared camera. This thermographic approach is intrinsically linear and absolute since the properties of the target are known and approximately independent of temperature. It is sufficiently sensitive that only one…
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2008
Irradiation of a metal by lasers or swift heavy ions causes the electrons to become excited. In the vicinity of the excitation, an electronic temperature is established within a thermalization time of 10–100 fs, as a result of electron-electron collisions. For short times, corresponding to less than 1 ps after excitation, the resulting electronic…
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2008
The paper reports on experiments carried out at JET to test the possibility of using some activating materials (e.g. 89Y, 167Er, 204Pb, 180Hf, 111Cd, etc.) to perform multi-foil neutron activation measurements. It is shown that apart from indium other materials can be successfully used in these measurements delivering more exact information about f…
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2007
The design of the ITER ICRF system has been under revision for several years. The paper presents the status of the design proposal based on a 24 strap antenna plug (6 poloidal by 4 toroidal short radiating conductors) in which the straps are passively combined in 8 poloidal triplets by means of 4-port junctions. These triplets are connected in para…
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2006
The Kamaboko III negative ion source, which was designed and built by JAERI, Naka, Japan, is a model 25% in linear dimensions of the reference design ion source for the International Thermonuclear Experimental Reactor ITER neutral beam injectors. The ion source is a magnetic multi-pole, arc discharge, source with 12 tungsten filaments. Cesium is ad…
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2005
Studies of the safety and environmental impacts of fusion, both of future power plants and of ITER, have shown that a good performance can be achieved. Although it is difficult to anticipate the regulatory regime in which future fusion power stations will be licensed, the areas of public and occupational safety and short and long-term environmental…
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2005
‘Trace Tritium Experiments’ (TTE) were successfully performed on JET in 2003. The Campaign marked the first use of tritium in JET plasmas since the Deuterium- Tritium Experiment (DTE1) Campaign in 1997, and was the first use of tritium in experiments under the EFDA organisation with the UKAEA as JET Operator. The safety and regulatory preparati…
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2004
The generalized Charney-Hasegawa-Mima equation is unstable to a four wave modulational instability whereby a coherent, monochromatic drift wave can drive a band of modes and associated zonal flows unstable. Although initially the fastest growing modes dominate, a secondary nonlinear instability later drives the longest wavelength zonal flow and its…
Showing 41 - 50 of 58 UKAEA Paper Results