TY - JOUR
T1 - Enhanced energy localization and heating in high contrast ultra-intense laser produced plasmas via novel conical micro-target design
AU - Rassuchine, J.
AU - D'Humières, E.
AU - Baton, S.
AU - Fuchs, J.
AU - Guillou, P.
AU - Koenig, M.
AU - Kodama, R.
AU - Nakatsutsumi, M.
AU - Norimatsu, T.
AU - Batani, D.
AU - Morace, A.
AU - Redaelli, R.
AU - Gremillet, L.
AU - Rousseaux, C.
AU - Dorchies, F.
AU - Fourment, C.
AU - Santos, J. J.
AU - Adams, J.
AU - Korgan, G.
AU - Malekos, S.
AU - Sentoku, Y.
AU - Cowan, T. E.
N1 - Publisher Copyright:
© 2008 IOP Publishing Ltd.
PY - 2008/6/12
Y1 - 2008/6/12
N2 - We report new experiments showing enhanced laser-target coupling and energy localization using nano-fabricated micro-conical Cu targets performed at the 100 TW CPA laser at LULI. A comparison was made between 1ω (λ = 1.057 μm, I = 1019 W/cm2) and 2ω (λ = 0.53 μm, I = 4-8 × 1018 W/cm2) irradiation to determine the effect of ASE induced preformed plasma filling the cone, using as principal diagnostics 2D Cu Kα imaging (transverse and rear-side), and high-resolution conical crystal spectroscopy of the Cu Kα bands. The 2ω irradiation exhibits laser absorption up to 50 μm deeper into the cone tip (versus at 1 ω), with a commensurately smaller Kα emission zone. Spectroscopy indicates a higher average charge state for the Cu emission at 2ω, with some shots exhibiting up to at least O-like emission. We deduce that micro-cone targets have similar performance in terms of material heating as a 50 μm diameter reduced mass target, despite a 900-fold larger mass. The observed enhancement in energy localization and heating in the cone geometry is supported by 2D collisional PIC simulations which indicate the presence of self-generated resistive magnetic field structures (≥ 10 MG) which confine the energetic electrons to the tip region.
AB - We report new experiments showing enhanced laser-target coupling and energy localization using nano-fabricated micro-conical Cu targets performed at the 100 TW CPA laser at LULI. A comparison was made between 1ω (λ = 1.057 μm, I = 1019 W/cm2) and 2ω (λ = 0.53 μm, I = 4-8 × 1018 W/cm2) irradiation to determine the effect of ASE induced preformed plasma filling the cone, using as principal diagnostics 2D Cu Kα imaging (transverse and rear-side), and high-resolution conical crystal spectroscopy of the Cu Kα bands. The 2ω irradiation exhibits laser absorption up to 50 μm deeper into the cone tip (versus at 1 ω), with a commensurately smaller Kα emission zone. Spectroscopy indicates a higher average charge state for the Cu emission at 2ω, with some shots exhibiting up to at least O-like emission. We deduce that micro-cone targets have similar performance in terms of material heating as a 50 μm diameter reduced mass target, despite a 900-fold larger mass. The observed enhancement in energy localization and heating in the cone geometry is supported by 2D collisional PIC simulations which indicate the presence of self-generated resistive magnetic field structures (≥ 10 MG) which confine the energetic electrons to the tip region.
U2 - 10.1088/1742-6596/112/2/022050
DO - 10.1088/1742-6596/112/2/022050
M3 - Conference article
AN - SCOPUS:66049108760
SN - 1742-6588
VL - 112
JO - Journal of Physics: Conference Series
JF - Journal of Physics: Conference Series
IS - Part 2
M1 - 022050
T2 - 5th International Conference on Inertial Fusion Sciences and Applications, IFSA 2007
Y2 - 9 September 2007 through 14 September 2007
ER -