Some characteristics of the picosecond laser produced plasma expanding across an externally applied magnetic field (0.6T) have been reported. Two to three times enhancement in X-ray emission from copper plasma has been observed for the laser intensity range ∼5 X 1011 to 5 X 1012 W/cm2. The X-ray yield has been found to increase with an increase in the magnetic field intensity. Enhancement in X-ray emission is correlated with confinement of expanding plasma either in external magnetic field or in high ambient gas pressure. Generation of some highfrequency instability and fast ions was also observed in the plasma along with bouncing of plasma near the β = 1 surface where kinetic pressure of plasma equals magnetic pressure.

Laser plasma experiments reveal rich interplay between laser plasma instabilities. The growth of stimulated Brillouin scattering (SBS) is one of the most significant constraints of laser fusion experiments. In this paper, a mechanism of stabilization of SBS process due to magnetic anisotropy has been presented. Magnetic anisotropy induced by the temporally exponentially growing nonoscillating magnetic moment from inverse Faraday effect (IFE) has been studied.It has been shown that for interaction of Nd laser (λ = 1.06 μm) on solid deuterium target the SBS growth rate (y) ∼ 3.45 ps and the phase velocities of the incident and scattered electromagnetic (EM) waves have been shown to decay exponentially (∼e∼λ1) in this SBS process resulting in wave-number mismatch.

The effect of arbitrary shapes of the two fluid interface on Richtmyer-Meshkov (RM) instability is investigated. It is seen that deviation from sinusoidality in the geometrical shapes has interesting influence on the overall growth rate. In the linear theoretic domain the RM instability may be actually reduced for suitable geometrical shape of the interface. The figures given demonstrate this aspect. This result is important in designing ICF target and also gives an idea to tailor laser pulse for optimum stability of RM modes.

The Second International Conference on the Frontiers of Plasma Physics and Technology was held in Goa, India, from February 21–25, 2005. This conference explored a number of fundamental and applied plasma physics topics. Special attention was focused on the exploration of frontiers in physics and technology of high energy density plasmas—a topic growing at a very fast pace due to the emergence of extremely powerful laser sources. Reviews on activities and new opportunities for large laser facilities in prominent laboratories of Asia, Europe, and Canada were presented. Talks on recent advances on laser driven Wakefield particle acceleration scheme were very exciting. This technology has a strong potential of revolutionizing the existing accelerator physics, technology, and radiation sources such as synchrotrons and X-ray free-electron lasers. Discussions were also given on the generation of extreme physical conditions similar to those existing in astrophysical objects, under laboratory conditions using intense lasers. This technique may lead to an easy and inexpensive way to simulate and understand a variety of astrophysical phenomena. This aspect of realization of astrophysical conditions in a laboratory has now become reality, and soon may lead to routine experiments. New applications of laser in the designs of light-crafts may soon become reliable.

The impedance mismatch technique was used for shock pressure amplification in two layered planar foil targets. Numerical simulation results using one-dimensional (1D) radiation hydrocode MULTI in two layer target consisting of polyethylene (CH2)n-aluminium (Al) and polyethylene (CH2)n-gold (Au), show a pressure enhancement of 12 and 18 Mbar, respectively (or a pressure jump of 1.64 and 2.54, respectively), from initial pressure of 7 Mbar in the reference material (polyethylene) using laser intensity of 5 × 1013 Watts/cm2 at 1.064 μm. The simulation data was also corroborated by experiments in our laboratory. Results of laser driven shock wave experiments for pressure enhancement studies in CH2-Al and CH2-Au targets are also presented. A Nd:YAG laser chain (2 J, 1.064 μm wavelength, 200 ps pulse duration FWHM) is used for generating shocks in the planar CH2 foils of thickness varying from 4 to10 μm, and in two layered CH2-Al (or CH2-Au) targets with 8 μm CH2 and 1.5 μm Al or Au .

A commercial mode locked cavity dumped Nd:YAG dye laser operating at 10 Hz repetition rate is modified to produce a high contrast (>5000:1) single laser pulse while maintaining the energy stability and high beam quality. A trigger generator biases the cavity dumping photodiode, which is triggered externally by a pulse from the microprocessor-based control unit controlling a ∼2 J/200 ps laser chain. In the laser chain, the high contrast (>5000:1) is achieved by an external pulse selector based on single Pockel's cell to select a single laser pulse of high contrast, which is a prerequisite for experimental study of the equation of state. Laser-induced shock velocity measurement in thin aluminum, gold on aluminum, and copper on aluminum foil targets using this modified laser system are also presented. The equation of state of Al, Au, and Cu obtained using an impedance matching technique are in agreement with the reported results of SESAME and simulation results.

We have simulated the shock Hugoniot of copper and uranium based on the results of first principles electronic structure calculations. The room temperature isotherm has been obtained by evaluating the accurate ground state total energies at various compressions, and the thermal and electronic excitation contributions were obtained by adopting isotropic models using the results obtained by the band structure calculations. Our calculations ensure smooth consideration of pressure ionization effects as the relevant core states are treated in the semi-core form at the ambient pressure. The pressure variation of the electronic Grüneisen parameter was estimated for copper using the band structure results, which leads to good agreement of the simulated shock Hugoniot with the measured shock data. The simulation results obtained for U are also compared with the experimental data available in literature and with our own data.

The acceleration of ions (∼108 cm/s) has been observed in the laser produced plasma expanding across an uniform magnetic field at low laser irradiance (∼5 × 1012 W/cm2). This acceleration was found correlated with the onset of instabilities in the plasma and decrease in the slope of X-ray emission with laser intensity. A large enhancement in the X-ray emission (E > 2 KeV) from plasma in the presence of magnetic field supports the observation of ion acceleration. An increase in the number of ions was noticed in the pressure range in which enhancement in the self-generated spontaneous magnetic field has already been established. Even scaling of both the variations with chamber pressure during rising part was found in close agreement, which further supports the correlation. The possibility of an external magnetic field in triggering the acceleration and space charge potential in generating a correlation (between ion acceleration and self-generated spontaneous magnetic field) has been discussed.

It is important to ameliorate the early time imprinting of nonuniformities due to laser radiation or target shell surface in an inertial confinement fusion (ICF) scheme. However, they will not prevent the instabilities which originate at the ablation surface due to acceleration of high density plasma by low density plasma. One of the methods discussed here is to combat the growth of instabilities at the ablation surface. The present work is aimed to control growth of hydrodynamic instability in laser irradiated target at moderate intensities. Laser (λ = 1.06 μm) radiation was focused on the plastic (base) target seeded with microinclusions of Al and Au at various concentrations. Targets had planar geometry and were of few microns in thickness. The target stability was studied using the optical backlighting technique. Shadowgrams of the seeded targets show a uniform motion of the target rear, whereas pure plastic targets break up under identical conditions. Results are analyzed by considering the X-radiation transport, coherent structure effects of the plasma like vortices, self-generated magnetic field in the accelerated target, and nonlinear conversion of long wavelength perturbation into short wavelength perturbation.