Plasma evolution in laser-irradiated hollow microcylinders

Abstract

Hollow microcylinder targets, 200–300 μm in diameter, have been internally irradiated at up to 5 · 1014 W/cm2 with Nd:glass laser pulses directed through an axial entrance slit. The plasma evolution in the interior of the cavities was diagnosed with a pinhole imaging X-ray streak camera and a Nomarski-type interferometer. Plasma collision near the center of the cylinder is observed about 300 ps after the irradiating laser pulse. The experimental results are confirmed by a one-dimensional Eulerian fluid code.

Some studies on picosecond laser produced plasma expanding across a uniform external magnetic field

“…This scheme has also been found useful in increasing the gain of the lasing medium of X-ray laser (Suckewer & Fishman 1980;Suckewer et al 1985) when operated in recombination regime as a result of increase in particle confinement, because in this case particle confinement time remains much larger than the electron temperature decay time and the plasma is cooled through the radiation losses. Enhancement in UV and visible emission from beryllium plasma in the presence of magnetic field have also been reported (Begimaculov et al 1992). An enhancement of ~ 100 in stimulated emission (along magnetic field) over spontaneous emission (perpendicular to magnetic field) of C vi 182 A line has been measured in the presence of 90 kG magnetic field.…”

“…It was observed that the X-ray signals from copper plasma were enhanced 2-3 times when the magnetic field was increased from 0.1 to 0.6 T. However no change was observed in X-ray intensity in the absence or presence of 0.01 T magnetic field. Generally the value of a has been reported to be ranging from 1.5 to 2.5 in the absence of magnetic field (Bleach & Nagel 1978;Rai et al 1995b). In this case X-ray detector with zapon filter was sensitive for soft as well as hard X-ray energy.…”

“…Laser produced plasma has been extensively studied using laser pulses of various time duration (ns-fs) providing irradiances ranging from 10' 2 to 10' 8 W/cm 2 (Cairns & Sanderson 1980;Radziemski & Cramers 1989). There is great interest in the generation of short time duration intense and small size X-ray source for applications such as plasma diagnostics in laser produced plasma and inertial confinement fusion (ICF) experiments, X-ray lithography, X-ray microscopy, and EXAFS (Radziemski & Cramers 1989), and so forth.…”

“…Several techniques have been reported in the literature (Balmer & Donaldson 1977;Richardson etal. 1980;Yaakobi et al 1981;Balmer et al 1990) to enhance the X-ray emission. Out of these experiments, investigation of laser produced plasma expanding across a static or DC magnetic field is interesting (Suckewer & Fishman 1980;Suckewer et al 1985;Enright & Burnett 1986) because magnetic field is one of the means to affect dynamics, ionization, and optical characteristics of the expanding plasma.…”

Bow shocks formed by plasma collisions in laser irradiated semi-cylindrical cavities

“…The collision and subsequent interaction of dense plasmas created by intense laser irradiation of cylindrical cavities are of interest for fundamental and practical reasons [1][2][3]. We have recently reported the study of semi-cylindrical cavity plasmas using soft X-ray laser interferometry and hydrodynamic simulations [4].…”