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Descripción
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| Fast ignition by laser-driven ion beams [1, 2] offers the advantages of their classical interaction with the imploded fuel and the relatively moderate ignition energies compared with hot electrons. Proton Fast Ignition (PFI) seems to be the most promising option because laser-to-proton conversion efficiencies are relatively high (» 12%) [3]. Mono-energetic heavier ion beams such as carbon have been proposed recently [4] as an alternative to the PFI scheme due to their better energy deposition in the compressed DT core and the lower ion currents required for ignition. However, the laser-to-carbon ion conversion efficiencies may be substantially lower (» 5%) than those found for protons [4, 5]. In this contribution, we will show that the two-beam PFI scheme proposed in Ref. [6] allows ignition of fuel targets compressed to 500 g/cm3 with a total energy around 8 kJ. The energy distribution of the proton beams is Maxwellian with a temperature of 4 MeV. If those protons were generated with an efficiency of 12%, the required laser energy would be 67 kJ @ w0 (l = 1.053 ìm) that is of the same order than those envisioned for future fast ignition facilities such as HiPER [7]. Simulations of fuel ignition by carbon ions with mean energies of 300 ¿ 450 MeV and energy spreads of 10% show higher coupling efficiencies and lower ignition energies than those found for protons. However, the use of carbon ions in fast ignition still depends on the experimental demonstration of a reasonably high laser-to-ion conversion efficiency. The minimum ignition energies obtained for ion beams will be compared with those found for fast electrons in order to assess laser beam requirements to demonstrate fast ignition. References [1] M. Roth et al., Phys. Rev. Lett. 86, 436 (2001). [2] M. Temporal, J.J. Honrubia and S. Atzeni, Phys. Plasmas 9, 3098 (2002). [3] R.A. Snavely et al., Phys. Rev. Lett. 85, 2945 (2000). [4] J.C. Fernandez et al., IFSA 2007 Proc., Kobe, Japan (2008), LA-UR-07-6236 (2007). [5] J. Badziak, Opto-Electron. Rev. 15, 1, (2007). [6] M. Temporal, Phys. Plasmas 13, 122704 (2006). [7] M. Dunne, Nature Physics 2, 2 (2006). P-5.125, Friday June 13, 2008 | |
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Internacional
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Si |
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Nombre congreso
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35th European Physical 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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Hersonissos, Creta, Grecia |
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Revisores
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Si |
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ISBN o ISSN
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2-914771-52-5 |
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DOI
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Fecha inicio congreso
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09/06/2008 |
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Fecha fin congreso
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13/06/2008 |
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Desde la página
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51251 |
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Hasta la página
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51254 |
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Título de las actas
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Europhysics Conference Abstracts, Vol. 32D |