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ABSTRACT: A simple analytical model is presented for hydrodynamic expansion of laser-produced plasma with a limited mass, which expands quasi-isothermally during laser irradiation and quasiadiabatically after turning off the laser. During the isothermal expansion, the masses undergo entire disintegration under a relatively long laser pulse, while the ions are being kept accelerated. This physical picture significantly contrasts with that described by the orthodox self-similar solution for a semi-infinite planar rarefaction wave. The two successive expansions, i.e., isothermal expansion followed by adiabatic expansion, are described, respectively, by different self-similar solutions, which are found to be connected smoothly with each other in time and space. The ion energy spectrum obtained by the model reproduces well experimental results obtained under different geometrical conditions. The maximum ion kinetic energy is also estimated in terms of the laser and target parameters.
Physics of Plasmas 06/2005; 12(6):062706-062706-8. · 2.15 Impact Factor
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ABSTRACT: We present X-ray radiograms from a high Mach number "complex"
blast wave interacting with a high-density (100 times the ambient)
sphere using a laser produced plasma. We show visualizations of data
from comparable parameter two-dimensional axisymmetric hydrodynamic
simulations, including density, dilatation (div u), and vorticity (curl
u). The simulation results are consistent with the X-ray radiograms,
thus providing heuristic guidance for future studies
IEEE Transactions on Plasma Science 03/2002; · 1.17 Impact Factor
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Y G Kang,
K Nishihara,
H Nishimura,
H Takabe,
A Sunahara,
T Norimatsu,
K Nagai,
H Kim,
M Nakatsuka,
H J Kong,
N J Zabusky
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ABSTRACT: We present x-ray shadowgraphs from a high Mach number ( approximately 20) laboratory environment that simulate outward flowing ejecta matter from supernovae that interact with ambient cloud matter. Using a laser-plastic foil interaction, we generate a "complex" blast wave (a supersonic flow containing forward and reverse shock waves and a contact discontinuity between them) that interacts with a high-density (100 times ambient) sphere. The experimental results, including vorticity localization, compare favorably with two-dimensional axisymmetric hydrodynamic simulations.
Physical Review E 11/2001; 64(4 Pt 2):047402. · 2.26 Impact Factor
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ABSTRACT: The collision of the remnant of supernova 1987A with its circumstellar ring is laboratory-simulated by using the Gekko XII
laser fusion facility at the Institute of Laser Engineering, Osaka University. The pure hydrodynamic approximation was applied
using the invariance of the Euler equations. The basic properties of the formation of a young supernova remnant and its collision
with the ring are illustrated. Shock wave propagation and plasma flow with triple wavy, vortex ringlike structures were observed
using gated X-ray shadowgraphy. The observed hydrodynamic behaviors compare favorably with one-and two-dimensional numerical
simulations and further illustrate important qualitative trends. Our experiments suggest the shock reverberation between the
ring and the contact discontinuity in the supernova remnant 1987A and resultant oscillation and enhancement of X-ray emission,
as well as the emergence of downstream vortex structures.
Plasma Physics Reports 01/2001; 27(10):843-851. · 0.65 Impact Factor
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H Nishimura,
S Fujioka,
T Okuno,
Y. Tao,
N Ueda,
T Ando,
T. Aota,
Y Yasuda,
S Uchida,
Y Shimada, [......],
Y. Norimatsu,
H Furukawa, Y.-G. Kang,
A. Sunahara,
K. Gamada,
M Murakami,
K Nishihara,
N Miyanaga,
Y Izawa,
K. Mima
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ABSTRACT: Properties of extreme ultraviolet (EUV) and particle emissions from laser-produced tin (Sn) plasma were experimentally investigated for use in industrial applications. Dependence of EUV emission on the initial thickness of Sn overcoat on a plastic sphere was studied to clarify the minimum mass needed to keep sufficient conversion to EUV and minimize plasma debris. EUV emission from low-density targets showed narrower spectra peaked at 13.5 nm, attributed to reduction of satellite line emissions in the spectrum foot and opacity broadening at the peak. It is shown that not only the EUV generation but also ion spectra are significantly affected by the Sn coat thicknesses.
http://dx.doi.org/10.1051/jp4:2006133243.
