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2011
A minimal model for magnetic reconnection and, generally, low-frequency dynamics in low-beta plasmas is proposed. The model combines analytical and computational simplicity with physical realizability: it is a rigorous limit of gyrokinetics for plasma beta of order the electron-ion mass ratio. The model contains collisions and can be used both in t…
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2011
Magnetic Cluster Expansion model is developed for bcc Fe-Cr alloys, and applied to the investigation of magnetic properties of these alloys for a broad interval of concentrations ranging from pure Fe to pure Cr, and for a broad interval of temperatures extending well over 1000 K. Finite-temperature configurations simulated using the Magnetic Cluste…
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2011
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2011
Among dust particles of various origins collected in the MAST vessel, large quantities of carbon nanoparticles are observed. They are produced in the coldest plasma regions from the nucleation of carbonaceous species originating from physical and chemical erosion of the graphitic plasma facing components. On the other hand, laboratory plasmas studi…
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2011
IBA techniques such as RBS, ERDA, NRA, or PIXE are highly complementary, and are often combined to maximize the extracted information. In particular, they have different sensitivities to various elements and probe different depth scales. The same is true for secondary ion mass spectrometry (SIMS), that can have much better detection limits for many…
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2011
The sawtooth instability in tokamak plasmas results in a periodic reorganization of the core plasma. A typical sawtooth cycle consists of a quiescent period, during which the plasma density and temperature increase, followed by the growth of a helical magnetic perturbation, which in turn is followed by a rapid collapse of the central pressure. The …
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2010
An avalanche photodiode based APD detector for the visible wavelength range was developed for low light level, high frequency beam emission spectroscopy BES experiments in fusion plasmas. This solid state detector has higher quantum efficiency than photomultiplier tubes, and unlike normal photodiodes, it has internal gain. This paper describes the …
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2010
The impact of resonance magnetic perturbations (RMP) on the structure of the edge transport barrier has been studied. A new model for the density pump-out mechanism during the stochastization of the plasma edge is proposed. The observed phenomena are explained as a result of the impact of the ambipolar electric field, which is modified during RMP, …
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2009
During high power commissioning of the JET LH launcher, the radiation and impurity release has been analyzed from various diagnostics: VUV and visible spectroscopy, bolometry. These two last diagnostics have lines-of-sight viewing the launcher and can provide information about the electron and/or impurity source localisation. Using a database of 80…
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2009
The commissioning of the ITER-Like ICRF Antenna (ILA) [1] on JET plasmas from May 2008 to April 2009 in various conditions (33, 42 and 47 MHz, L- and H-mode, antenna strap-plasma separatrix distances of ~9 to 17 cm) has provided relevant information for future antenna design and operation. The maximum power density achieved was 6.2 MW/m2 in L-mode …
Showing 141 - 150 of 183 UKAEA Paper Results