Encontrados 7 documentos, a visualizar página 1 de 1
Exploring the nature of collisionless shocks under laboratory conditions
Stockem, A.; Fiuza, F.; Bret, A.; Fonseca, R. A.; Silva, L. O.WOS:000331215400005 (Nº de Acesso Web of Science) ; Collisionless shocks are pervasive in astrophysics and they are critical to understand cosmic ray acceleration. Laboratory experiments with intense lasers are now opening the way to explore and characterise the underlying microphysics, which determine the acceleration process of collisionless shocks. We determine the shock character – electrostatic or electro...
Ion acceleration from laser-driven electrostatic shocks
Fiuza, F.; Stockem, A.; Boella, E.; Fonseca, R. A.; Silva, L. O.; Haberberger, D.; Tochitsky, S.; Mori, W. B.; Joshi, C.WOS:000320000000092 (Nº de Acesso Web of Science) ; Multi-dimensional particle-in-cell simulations are used to study the generation of electrostatic shocks in plasma and the reflection of background ions to produce high-quality and high-energy ion beams. Electrostatic shocks are driven by the interaction of two plasmas with different density and/or relative drift velocity. The energy and number of ions reflect...
Large-scale magnetic field generation via the kinetic Kelvin-Helmholtz instabil...
Alves, E.P.; Grismayer, T.; Martins, S. F.; Fiuza, F.; Fonseca, R. A.; Silva, L. O.WOS:000300611100001 (Nº de Acesso Web of Science) ; “Prémio Científico ISCTE-IUL 2013” ; Collisionless plasma instabilities are fundamental in magnetic field generation in astrophysical scenarios, but their role has been addressed in scenarios where velocity shear is absent. In this work we show that velocity shears must be considered when studying realistic astrophysical scenarios, since these trigger the co...
Weibel-Instability-Mediated Collisionless Shocks in the Laboratory with Ultrain...
Fiuza, F.; Fonseca, R. A.; Tonge, J. W.; Mori, W. B.; Silva, L. O.WOS:000305032100015 (Nº de Acesso Web of Science) ; “Prémio Científico ISCTE-IUL 2013” ; The formation of nonrelativistic collisionless shocks in the laboratory with ultrahigh intensity lasers is studied via ab initio multidimensional particle-in-cell simulations. The microphysics behind shock formation and dissipation and the detailed shock structure are analyzed, illustrating that the Weibel instability pla...
Laser-Driven Shock Acceleration of Monoenergetic Ion Beams
Fiuza, F.; Stockem, A.; Boella, E.; Fonseca, R. A.; Silva, L. O.; Haberberger, D.; Tochitsky, S.; Gong, C.; Mori, W. B.; Joshi, C.WOS:000311284200008 (Nº de Acesso Web of Science) ; “Prémio Científico ISCTE-IUL 2013” ; We show that monoenergetic ion beams can be accelerated by moderate Mach number collisionless, electrostatic shocks propagating in a long scale-length exponentially decaying plasma profile. Strong plasma heating and density steepening produced by an intense laser pulse near the critical density can launch such shocks that...
The impact of kinetic effects on the properties of relativistic electron--posit...
Stockem, A.; Fiuza, F.; Fonseca, R. A.; Silva, L. O.WOS:000312579500058 (Nº de Acesso Web of Science) ; “Prémio Científico ISCTE-IUL 2013” ; We assess the impact of non-thermally shock-accelerated particles on the magnetohydrodynamic (MHD) jump conditions of relativistic shocks. The adiabatic constant is calculated directly from first-principles particle-in-cell simulation data, enabling a semi-kinetic approach to improve the standard fluid model and allowing ...
Production of Picosecond, Kilojoule, and Petawatt Laser Pulses via Raman Amplif...
Trines, R. M. G. M.; Fiuza, F.; Bingham, R.; Fonseca, R. A.; Silva, L. O.; Cairns, R. A.; Norreys, P. A.WOS:000301051200006 (Nº de Acesso Web of Science) ; “Prémio Científico ISCTE-IUL 2012” ; Raman amplification in plasma has been promoted as a means of compressing picosecond optical laser pulses to femtosecond duration to explore the intensity frontier. Here we show for the first time that it can be used, with equal success, to compress laser pulses from nanosecond to picosecond duration. Simulations show up ...
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