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Hot electrons created by short, intense laser pulses can heat solid density material to temperatures of order 500 eV. Inertial confinement can maintain such hot-dense plasmas for times of order 10 ps. This provides a platform for measurement of basic properties of hot dense matter, such as opacity and equation-of-state. In this paper we describe the role of computational modeling in the design and analysis of such opacity experiments. We describe a method to model the hot electron transport and deposition and the resulting target radiation-hydrodynamics. We present several design concepts to achieve uniform, long-lasting plasmas.

A novel method to realize solid metallic hydrogen is proposed as a new path to high energy density states of hydrogen. High-pressured atomic hydrogen could be metalized at a density of 0.1 g/cm 3 below 1000 K, which is much less than the previously expected in the solid molecular hydrogen(about 1.43 g/cm 3 at 300 K). This density will be obtained at pressures of less than 100 GPa with a conventional static compression technique. Atomic hydrogen at this density could be created from molecular hydrogen using three-photon absorption of a 250 nm short pulse laser light to cause photodissociation. Calculations taking into account the wavefunction of the molecular hydrogen are presented.

The fast ignition realization experiment (FIREX) project is progressing. The new short pulse laser system, LFEX laser, has been completely assembled and one of the four beamlets is now in operation. A fast-ignition experiment was performed using this single short pulse combined with the Gekko XII implosion laser. The energy of the GXII implosion laser was about 2 kJ and the pulse width was 1.5 ns. The energy of the LFEX laser was increased upto 800 J and two pulse durations 5 and 1.6 ps were compared. Targets were deuterated plastic shells with gold cones. It was found that the neutron yield was increased by a factor of 30 as a result of the fast electron-induced heating in LFEX 1.6 ps shot. The estimated coupling efficiency between the LFEX laser pulse and the compressed fuel was low (less than 5%). This may be due to pre-plasma formed by light arriving at the target before the main laser pulse. Further investigations and attempts to overcome these problems are now in progress. © 2011 Elsevier B.V.

Short pulse laser ablation of a model two-component system has been simulated using a coarse-grained molecular dynamics (MD) model. A system with two disparate components (hard and soft) has been considered, based broadly on the properties of hard tissue. The existence of distinct regimes of material ejection has been identified and the processes leading to the ablation have been investigated. In the lower fluence regime gaseous particles of the soft component stream from the hard matrix but there is no ejection of the hard component. In the higher fluence regime chunks of the hard component are ejected simultaneously with the soft component.

Short-pulse laser heating offers the opportunity of creating plasmas of very high energy density in the laboratory. Measurements of the radiative properties of such plasmas are now starting to be performed. Some attempt has been made to reduce the spatial gradients of temperature and density by using buried layer targets. We show in this paper that through extensive computational design work, it is possible to make further reductions in such gradients, thereby significantly increasing the value of such experiments in checking theoretical models of the radiative opacity.

A method of multi-pulse discriminating frequency and high probability average value filtering is presented for offset frequency locking with ns laser pulses. In the experiment, the frequency locking for cavity-dumped CO 2 laser with 100 ns pulse width and the repetition rate of 10 kHz was studied. The precision was up to ±2 MHz at the heterodyne frequency 90 MHz. However, it is more than ±10 MHz for the single pulse discriminating frequency. This method can also be applied to laser offset frequency locking for many kinds of short pulse lasers.

A Nd:glass and Ti:sapphire hybrid laser system capable of producing 0.2-J/1-ps pulses has been developed. Gain narrowing is not observed after the 10 3 times amplification by the Nd:glass amplifier, which shows the potentiality of producing 1-J/1-pspulses from a Ti:sapphirc and Nd:glass hybrid laser system.

The first experimental observations of a plasma produced in a vapor of C60 molecules with a high‐intensity subpicosecond KrF laser (6×1015 W/cm2) are reported. It differs from a plasma created in an ordinary carbon preplasma by reaching much higher ionization stages under the same experimental conditions. This remarkable property of C60 molecules (and other clusters) opens new prospects for short‐pulse driven X‐ray lasers.

Interior cracking was generated in KCl, LiF and MgO single crystals using a focused, short pulse laser. The laser-induced damage region in LiF and MgO crystals was composed of a damage core and three orthogonal penny-like cracks along {100} planes. In KCl crystals an extended cleavage crack was generated on just one side of the core. The detailed features were examined by optical and scanning electron microscopy.

Computer simulations have been made of interferograms produced in a typical short pulse laser produces plasma experiment. It is shown that interferometer focussing accuracy becomes increasingly critical as the plasma profile steepening becomes stronger and that there is a corresponding decrease in the maximum electron density that can be probed.

Computer simulations have been made of interferograms produced in typical short pulse laser produced plasma experiments. It is shown that for certain plasma profiles and values of scale length the reconstructed profile is an inaccurate representation of the original profile. It is also shown that the interferometer focussing accuracy affects the maximum measurable electron density and the implied plasma scale length.