Energy deposition of highly relativistic laser pulses into solid and near solid density high Z plasmas

HOLLINGER, R; S WANG; KAYMAK, V; J. J. ROCCA; A ROCKWOOD; CAPELUTO, M G; S. SHLYAPTSEV; A. MOREAU; WANG, Y; A PUKHOV

Conferencia; 61st Annual Meeting of the APS Division of Plasma Physics. Bulletin of the American Physical Society.; 2019

61st Annual Meeting of the APS Division of Plasma Physics. Bulletin of the American Physical Society. October 21?25, 2019; Fort Lauderdale, Florida Session YO4: AB: Intense Short Pulse Laser-Plasma Interactions. Abstract: YO4.00003The irradiation of near solid density, high Z nanostructure arrays at moderately relativistic intensities (ao = 1) offers nearly complete absorption of the laser light, which penetrates deep into the array [1]. As the intensity increases, however at highly relativistic intensities (ao = 20), the wires explode before the peak of the laser pulse forming a plasma exceeding even the relativistically corrected electron density, on the order of 1023 electrons/cc. Despite the formation of this supercritical density surface, the laser energy is still deposited deep into the nanowires by accelerated high energy electrons that ionize gold up to Au+69 (Ne-like Au). Ionized K shell spectroscopy of buried Ni tracers reveals the heat penetration depth in solid density Au slab targets and near solid density Au nanowire plasmas is >1 micron and >5 micron, respectively.These experimental results are in agreement with fully relativistic three dimensional particle in cell simulations. [1] M.A. Purvis et al Nature Photonics 7, 796 (2013)