Investigations on the effect of target angle on the stagnation layer of colliding laser produced plasmas of aluminum and silicon

Abstract

The temporal and spatial characteristics of two colliding laser produced plasmas are investigated over a range of flat to wedge-shaped targets for aluminum and silicon. Fast-gated visible photography was used to investigate how the length and width of the stagnation evolved over timescales from 300 to 500 ns with filters used to help to separate the emission from neutral and higher ionization states. The velocity of the stagnation layer was measured to be in the range of 3.8–6.6×106 cm/s. The length of the stagnation layer was observed to increase as the wedge angle decreased from 180° to 80°. Time-resolved spectra were also recorded, which helped to reveal the dominant ion stage in a given time interval. Based on this analysis, the longest and most homogenous stagnation layers appear to be comprised of mostly neutral and singly ionized species. Line widths were used to estimate electron densities of 1×1017cm−3 and temperatures of 1.9–2.1 eV, which remained fairly constant over the timescales observed. The analysis suggests that there is significant collisional reheating of the stagnation layer followed by radiative recombination and that the stagnation layer dynamics are not sensitive to small changes in mass.

Expansion Dynamic and Characterization of Stagnation Layer in Laterally Colliding Plasmas: Dependence of Observation Bandwidth and Plasma Plume Separation

“…In this work, the technique and analytical procedure for the stagnation layer expansion dynamics of specific ion and neutral species were explained and studied using time-resolved fast imaging in the visible spectral range using bandpass filter 450nm (FWHM 40±8 nm) which can add rich insight and further explanations to other contributions related to colliding laser-produced plasma technologies [18], [20]. The elements investigated were Aluminum (Z=13) and Silicon (Z=14).…”

“…laser energy (EL) = 670mJ). The FWHM pulse duration of Continuum Surelite III has been measured by the oscilloscope at t  5.360.28 ns and the spot diameter were approximately 29.4 μm @ f = 100 mm and 36.8 μm @ f = 125 mm (FWHM) [18].…”

Influence of laser-induced Au-plasma plume collision on the efficiency of x-ray radiations and the energy-transport process relevant to ICF

“…Plasma collision is a Universe phenomenon widely existing in High Energy Density Physics (HEDP) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17], laboratorybased astrophysics [2,[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36], and Inertial Confinement Fusion (ICF) projects [37]. Since rich dynamic physics exist during the colliding process, a series of different configurations have been proposed by multi-beam laser-plasma interactions.…”

“…Since rich dynamic physics exist during the colliding process, a series of different configurations have been proposed by multi-beam laser-plasma interactions. Dynamics of the stagnation and penetration in the colliding region have also been studied with millijoule-or subjoule-lasers in previous work [1][2][3][4][5][6][7][8][9][10]. In most HEDP experiments, it is always applied for the improvement of ion temperature and further for the enhancement of energy conversion efficiency from the laser to x-ray [11][12][13][14][15] or neutron [16,17] sources.…”