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Tokar M.Z.,EURATOM | Moradi S.,Laboratory for Plasma Physics Brusells
Nuclear Fusion | Year: 2011

The radial profiles of deuteron and triton densities in a fusion tokamak reactor are computed by taking into account anomalous transport due to ion temperature gradient and trapped electron drift instabilities in the plasma core and neoclassical transport in plateau-banana regimes, residual anomalous diffusion and convection triggered by edge localized modes in the edge transport barrier. The charged particle sources due to influx of neutral particles through the separatrix and ablation of frozen pellets in the plasma interior are optimized by searching for conditions providing the minimal outflow of unburned tritons to divertor target plates and their exhaust by pumping systems. It is demonstrated that such conditions correspond to fuelling of deuterium plasma component with gas puffing and of tritium with pellets and a ratio of deuteron/triton densities close to 2/1 at the separatrix. Effects of the absolute level and the ion mass dependence of neoclassical and anomalous transport contributions, of the position where neutrals enter the confined volume through the separatrix on the radial profiles of the ion densities are investigated. © 2011 IAEA, Vienna. Source

Ongena J.,Laboratory for Plasma Physics Brusells | Ogawa Y.,University of Tokyo
Energy Policy | Year: 2016

The paper gives an overview of fusion research in the world. The prospects for fusion as an energy source for the future are reviewed. Environmental compatibility, safety and resources are discussed. © 2016 Elsevier Ltd. Source

Kazakov Y.O.,Laboratory for Plasma Physics Brusells | Fulop T.,Chalmers University of Technology
Physical Review Letters | Year: 2014

A Reply to the Comment by Kim and Johnson. © 2014 American Physical Society. Source

Koch R.,Laboratory for Plasma Physics Brusells
Fusion Science and Technology | Year: 2010

This lecture complements the three previous lectures1,2,3 on waves by addressing, on the basis of elementary and intuitive treatment, the process of coupling of electromagnetic power to plasma. Coupling is here meant in a broad sense. It consists of four different steps, (i) The first one is the coupling of vacuum electromagnetic power to plasma waves. An elementary antenna coupling theory is given. The state of the art in coupling models and status of comparisons with experiments are briefly discussed. (ii) The second is the transfer of plasma wave energy to particle energy. The resonant processes leading to this transfer are described in a heuristic way. (iii) The third one is the build-up of fast particle populations. It will be outlined through a sketch of quasilinear diffusion for the simple case of Landau damping, (iv) The last step is the conversion of power through the resonant particle population to bulk plasma heating by collisions, which will be briefly addressed. Source

Koch R.,Laboratory for Plasma Physics Brusells
Fusion Science and Technology | Year: 2010

The heating of plasmas by fast ions, with a focus on Neutral Beam Injection (NBI), is reviewed. First, the need of auxiliary heating and current drive systems in fusion machines is outlined. For the particular case of tokamaks, the limitations of ohmic heating are discussed. The different ways of generating fast particles in plasmas are presented. The principle of operation of neutral beam injectors is explained. Positive-ion (PNBI) and negativeion (NNBI) based concepts are discussed. Next, the physical processes by which the beam transfers energy to the plasma, namely ionisation and slowing-down are described. For both, an elementary theory is given, whereby simple approximations to the distribution functions of beam injected ions and of alpha particles in reactors are obtained. Applications of NBI to heating, current drive and rotation drive are reviewed and the prospects of NBI for ITER are commented. Source

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