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Descripción
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| Fast ignition of inertial fusion targets separates fuel compression from hot spot heating to reduce significantly compression and symmetry requirements of the standard central ignition scheme. Electron-driven fast ignition of conically guided targets is a promising option that is being considered to demonstrate ignition in future facilities such as HiPER [1]. However, the complexities associated with this option have raised several physical issues not fully understood yet, such as the survival of the cone tip during fuel implosion and compression and fast electron generation in cones by ultra high intensity (UHI) lasers. Here, we report our progress on electron transport from the cone tip to the dense core and estimate the ignition energies of the UHI laser beam to ignite a target. Integrated simulations have been performed by combining 2D PIC calculations for electron acceleration with a 2D hybrid model for fast electron energy deposition coupled to plasma hydrodynamics and ignition physics. Recently, we have reported resistive filamentation and magnetic collimation of relativistic electron beams for beam currents around 1 GA and pulses of 10 ¿ 20 ps [2]. Beam collimation reduces significantly the ignition energies of the imploded fuel and depends strongly on the initial distribution function of relativistic electrons. In order to improve the characterisation of the fast electron source, we have performed 2D PIC simulations [3] to obtain the parameters (i.e. size, spectrum and angular distribution) of the beam used in electron transport calculations. We have found that the magnetic collimation of the fast electron beam is reduced substantially due to the angular distribution provided by PIC simulations. This implies a significant increase of the ignition energies when compared with previous studies [2]. Results about the energy deposition of fast electrons in the fuel, the role played by the self-generated fields, the overall coupling efficiency with the dense fuel and the energy requirements of the UHI laser beam for ignition are presented and discussed. | |
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Internacional
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Si |
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Nombre congreso
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37th EPS Conference on Plasma Physics |
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Tipo de participación
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960 |
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Lugar del congreso
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Dublin, Irlanda |
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Revisores
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Si |
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ISBN o ISSN
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2-914771-62-2 |
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DOI
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Fecha inicio congreso
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21/05/2010 |
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Fecha fin congreso
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25/06/2010 |
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Título de las actas
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Europhysics Conference Abstracts: Vol. 34A |