Filamentation and jets in line-focused laser-produced plasmas

Proceedings of LEOS'94, 1994

X-Ray Lasers 2016, 2018

When short wavelength extreme ultraviolet (EUV) and x-ray laser radiation is focused onto solid targets, narrow deep features are ablated and a dense, low temperature plasma is formed. We examine the radiation dominated plasma formed by 46.9 nm laser radiation focused onto solids and show that ionization can be significantly modified by electron degeneracy effects. Some experimental and theoretical considerations for investigating the interaction of capillary discharge lasers operating at 46.9 nm with solid and gas targets are presented.

Applied Physics Letters, 2009

Our recent experimental results have proved that the formation of plasma jets is a fundamental process accompanying the laser produced plasma expansion, if a massive planar target with relatively high atomic number (Z) is irradiated by a defocused laser beam. It is impossible to get the plasma jet from light target material like Al or plastic. Experimental results presented here demonstrate differences in both the plasma configuration and the plasma source geometry between Cu (high-Z material) and plastic (low-Z material) targets. The experiment was carried out at the PALS iodine laser. An attempt of explanation of differences in the plasma configuration was taken by means of numerical simulations using the two-dimensional hydrodynamic code ATLANT-HE.

Pramana, 2000

An investigation of x-ray emission from Cu plasma produced by 1.054 m Nd:glass laser pulses of 5 ns duration, at ¾ ¢ ½¼ ½¾ 2 ¢½¼ ½¿ W cm ¾ is reported. The x-ray emission has been studied as a function of target position with respect to the laser beam focus position. It has been observed that x-ray emissions from ns duration plasma show a volume effect similar to subnanosecond plasmas. Due to this effect the x-ray yield increases when target is moved away relative to the best focal plane of the laser beam. This result supports the theoretical model of Tallents and has also been testified independently using suitably modified theoretical model for our experimental conditions. While above result is in good agreement with similar experimental results obtained for sub-nanosecond laser produced plasmas, it differs from result claiming filamentation rather than pure geometrical effect leading to x-ray enhancement for ns plasmas.

Physical Review Letters, 1974

C 0 2 Laser (K. Manes) . C 0 2 Target Chamber (S. Glaros) . X-Ray Measurements (W. Slivinsky) . References .

Physical Review Letters, 1989

Intense laser light filamentation in a hydrogen plasma is investigated using a two-dimensional hydrodynamic simulation code. The laser paraxial wave equation is used to study the focusing which results from a Gaussian hot-spot intensity perturbation. It is found that diffraction increases the scale size of small-scale of-axis filamentation, and significantly raises the ponderomotive self-focusing intensity threshold. Radially propagating density Auctuations, contributing to small-scale focusing, are observed due to the self-consistent treatment of hydrodynamics in the simulations.

IEEE Conference Record - Abstracts. 2005 IEEE International Conference on Plasma Science, 2005

High-power pulsed lasers emitting IR and visible radiation with intensities ranging between 10 8 and 10 16 W/cm 2 , pulse duration from 0.4 to 9 ns and energy from 100 mJ up to 600 J, operating in single mode or in repetition rate, can be employed to produce non-equilibrium plasma in vacuum by irradiating solid targets. Such a laser-produced plasma generates highly charged and high-energy ions of various elements, as well as soft and hard X-ray radiations. Heavy ions with charge state up to 58+ and kinetic energy up to 10 MeV are detected. The plasma emits ion current densities of the order of tens of mA/cm 2 . Interesting application possibilities of the generated plasmas concerning the ion implantation technique, the laser ion sources, the high intensity and resolution X-ray sources, the laser propulsion technique and the nuclear reaction of light elements are presented and discussed.

Physical Review E, 2010

The physical mechanisms driving the collimation of dense plasma jets created by low-energy ͑ϳ0.6 J͒ laser pulse irradiation of triangular grooves were studied for different target materials using soft-x-ray interferometry and hydrodynamic code simulations. The degree of collimation of jets created by irradiating C, Al, Cu, and Mo targets at intensities of I =1ϫ 10 12 W cm −2 with 120 ps laser pulses was observed to increase significantly with the atomic number. Radiation cooling is found to be the cause of the increased collimation, while the main effect of the increase in mass is to slow the jet evolution.

Physical Review Letters, 1989

We have observed plasma jets from laser-irradiated gold disk targets. The structures originate from low-intensity regions of the incident laser beam but propagate much faster than similar density surfaces from higher-intensity regions. The material is both cold and dense, as evidenced by its emission of soft x rays and absorption of hard x rays.

In this review, the physics of short-pulse laser-produced plasmas at moderate intensities is described, together with applications to X-ray sources and material processing.