The problems concerning the development of high f-number spectrographs with high spectral and spatial resolution using holographic reflecting gratings, for the study of processes of harmonic generation in laser plasmas are considered. The concave holographic gratings and spectrograph schemes used in the “Delfin-1” installation are described. The anomalous generation of ω0 and 2ω0 harmonics from the subcritical density plasma region has been observed experimentally. Possible interpretations of the observed effect are given.

Success in inertial confinement fusion (ICF) requires sophisticated, characterized targets. The increasing fidelity of three-dimensional (3D), radiation hydrodynamic computer codes has made it possible to design targets for ICF which can compensate for limitations in the existing single shot laser and Z pinch ICF drivers. Developments in ICF target fabrication technology allow more esoteric target designs to be fabricated. At present, requirements require new deterministic nano-material fabrication on micro scale.

A criterion for a two temperature plasma nuclear fusion ignition is derived by using a common model. In particular, deuterium-tritium (DT) and proton–boron11 (pB11) are considered for pre-compressed plasma. The ignition criterion is described by a surface in the three-dimensional space defined by the electron and ion temperatures Te, Ti, and the plasma density times the hot spot dimension, ρ·R. The appropriate fusion ion temperatures Ti are larger than 10 keV for DT and 150 keV for pB11. The required value of ρ·R for pB11 ignition is larger by a factor of 50 or more than for DT, depending on the electron temperature. Furthermore, our ignition criterion obtained here for pB11 fusion is practically impossible for equal electron and ion temperatures. In this paper it is suggested to use a two temperature laser induced shock wave in the intermediate domain between relativistic and non-relativistic shock waves. The laser parameters required for fast ignition are calculated. In particular, we find that for DT case one needs a 3 kJ/1 ps laser to ignite a pre-compressed target at about 600 g/cm3. For pB11 ignition it is necessary to use more than three orders of magnitude of laser energy for the same laser pulse duration.

We have performed extensive one dimensional particle-in-cell (PIC) simulations to explore generation of electrostatic waves driven by two-stream instability (TSI) that arises due to the interaction between two symmetric counterstreaming electron beams. The electron beams are considered to be cold, collisionless and magnetic-field-free in the presence of neutralizing background of static ions. Here, electrons are described by the non-extensive q-distributions of the Tsallis statistics. Results shows that the electron holes structures are different for various q values such that: (i) for q > 1 cavitation of electron holes are more visible and the excited waves were more strong (ii) for q < 1 the degree of cavitation decreases and for q = 0.5 the holes are not distinguishable. Furthermore, time development of the velocity root-mean-square (VRMS) of electrons for different q-values demonstrate that the maximum energy conversion is increased upon increasing the non-extensivity parameter q up to the values q > 1. The normalized total energy history for a arbitrary entropic index q = 1.5, approves the energy conserving in our PIC simulation.

An improved high luminosity, easily spectrally tunable backlighting scheme based on a spherically bent crystal is considered in this paper. Contrary to the traditional backlighting scheme, we used crystal far from normal incidence, and the backlighter source was inside the Rowland circle. With the presented configuration, we obtained a spatial resolution up to 8 µm in the desired direction with an X-ray backlighting energy close to 5 keV. Detailed discussions and ray-tracing calculations show that with this convenient scheme resolution down to 5 µm can be achieved. A dedicated application to high energy density physics is presented: the radiography of shock compressed matter.

The theory of magnetic field generation due to the interaction of short relativistic laser pulses with underdense plasmas has been developed. The magnetic field is generated due to the inverse Faraday effect occurring witha circularly polarized laser pulse. The spatial distribution of the magnetic field is investigated. It is shown that the magnetic field magnitude depends on the relationship between the laser beam radius and the plasma skin-depth.

The effect of medium temperature upon characteristic of stimulated Brillouin scattering (SBS) and SBS optical limiting is investigated. The physical mechanism behind is analyzed theoretically and experimentally verified in Continuum's Nd: YAG Q-switched laser system using FC-72 as the SBS medium. The temperature affects the electrostrictive coefficient, refractive index, density and acoustic velocity of the medium weakly. In contrast, the kinematic viscosity, which is inversely proportional to the temperature, is related to gain coefficient and phonon lifetime and thus greatly affects the SBS characteristics. Therefore, in the low temperature, the kinematic viscosity is usually high, which can lead to a small gain coefficient and a short phonon lifetime. Therefore, the SBS characteristic can be changed by controlling the temperature to a great extent.

We investigate the Fokker–Planck Equation (FPE) in which we retain electron–ion and electron–electron collision terms, as well as the inverse-bremsstrahlung absorption term. We exhibit asymptotic solutions, which are then used in a linear perturbation theory ‘à la Spitzer’, to calculate local transport coefficients. Their values can differ drastically from classical results, which in turn alters hydrocode simulations.

A method of generating flat-top waveform in the time-domain based on stimulated Brillouin scattering (SBS) using medium with short phonon lifetime is proposed. In theory, the transmitted pulse is simulated in the case of several media with different phonon lifetime. In experiment, FC-72 and HT-270, which differ significantly in the phonon lifetime, are exploited in the experiment. Both the theoretical and experimental results indicate that, when choosing medium with short phonon lifetime, the top is almost a platform, while there is a peak in the front and a platform thereafter when choosing medium with long phonon lifetime.

An accurate turbulent mixing model for gravitationally induced instabilities with arbitrarily variable accelerations has been developed to capture the following physical aspects: (1) directed transport, (2) correct buoyancy forces, (3) turbulence diffusion, and (4) geometrical aspects. We present the two-structure two-fluid two-turbulence concept (2SFK), which consistently answers these requirements by identifying the large-scale transport structures in a statistical approach. An example of a 2SFK-based model is given and applied to the Rayleigh–Taylor case.

We report on a compact, all-glass laser using a fiberless CPA technique as a potential system for the generation of extreme high-contrast picosecond pulses in the terawatt power range. New exciting experiments in the field of laser-matter interaction at extremely high intensities require both a high output energy and a very high peak to background intensity ratio (contrast). At present the system delivers 1.5 ps-pulses of 1.5-J energy with an intensity contrast of 4.109.

Several choices exist in the design and production of capsules intended to ignite and propagate fusion burn of the deuterium–tritium (D–T) fuel when imploded by indirect drive at the National Ignition Facility (NIF). These choices include ablator material, ablator dopant concentration and distribution, capsule dimensions, and X-ray drive profile (shock timings and strengths). The choice of ablator material must also include fabrication and material characteristics, such as attainable surface finishes, permeability, strength, transparency to radio frequency and infrared radiation, thermal conductivity, and material homogeneity. Understanding the advantages and/or limitations of these choices is an ongoing effort for LLNL and LANL designers. At this time, simulations in one-, two-, and three-dimensions show that capsules with either a copper-doped beryllium or a polyimide (C22H10N2O4) ablator material have both the least sensitivity to initial surface roughnesses and favorable fabrication qualities. Simulations also indicate the existence of capsule designs based on these ablator materials which ignite and burn when imploded by less than nominal laser performance (900-kJ energy, 250-TW power, producing 250-eV peak radiation temperature). We will describe and compare these reduced-scale capsules, in addition to several designs which use the expected 300-eV peak X-ray drive obtained from operating the NIF laser at 1.3 MJ and 500 TW.

Energy enhancement by a circularly polarized laser pulse during acceleration of the electrons by a Gaussian laser pulse has been investigated. The electrons close to the temporal peak of the laser pulse show strong initial phase dependence for a linearly polarized laser pulse. The energy gained by the electrons close to the rising edge of the pulse does not show initial phase dependence for either linearly- or circularly-polarized laser pulse. The maximum energy of the electrons gets enhanced for a circularly polarized in comparison to a linearly polarized laser pulse due to axial symmetry of the circularly polarized pulse. The variation of electron energy with laser spot size, laser intensity, initial electron energy, and initial phase has been studied.

A high-power source of ultrawideband radiation with elliptical polarization of the field has been created. The source includes a monopolar pulse generator, a bipolar pulse former, a wave transformer with the power divider, and a four-element array of cylindrical helical antennas. The array was excited by bipolar pulses of the length 1 ns and amplitude 225 kV. In the experiments, the pulses of the elliptically polarized radiation with the effective potential of 440 kV and high stability at a pulse repetition rate of 100 Hz were obtained.

A kinetic theory for quantum many-particle systems in time-dependent electromagnetic fields is developed based on a gauge-invariant formulation. The resulting kinetic equation generalizes previous results to quantum systems and includes many-body effects. It is, in particular, applicable to the interaction of strong laser fields with dense correlated plasmas. Numerical results are obtained for the cycle-averaged electron–ion collision frequency in a high-frequency field.

A new multiphase buoyancy-drag model is developed for the study of Rayleigh-Taylor and Richtmyer-Meshkov instabilities in dusty gases, extending on a counterpart single-phase model developed in the past by Srebro et al. (2003). This model is applied to single- and multi-mode perturbations in dusty gases and both Rayleigh-Taylor and Richtmyer-Meshkov instabilities are investigated. The amplitude for Rayleigh-Taylor growth is observed to be contained within a band, which lies within limits identified by a multiphase Atwood number that is a function of the fluid densities, particle size, and a Stokes number. The amplitude growth is subdued with (1) an increase in particle size for a fixed particle number density and with (2) an increase in particle number density for a fixed particle size. The power law index for Richtmyer-Meshkov growth under multi-mode conditions also shows dependence to the multiphase Atwood number, with the index for the bubble front linearly decreasing and then remaining constant, and increasing non-linearly for the spike front. Four new classes of problems are identified and are investigated for Rayleigh-Taylor growth under multi-mode conditions for a hybrid version of the model: (1) bubbles in a pure gas rising into a region of particles; (2) spikes in a pure gas falling into a region of particles; (3) bubbles in a region of particles rising into a pure gas; and (4) spikes in a region of particles falling into a pure gas. Whereas the bubbles accelerate for class (1) and the spikes for class (4), for classes (2) and (3), the spikes and bubbles, respectively, oscillate in a gravity wave-like phenomenon due to the buoyancy term changing sign alternatively. The spike or bubble front, as the case may be, penetrates different amounts into the dusty or pure gas for every subsequent penetration, due to drag effects. Finally, some extensions to the presently developed multiphase buoyancy-drag model are proposed for future research.

Monoenegetic ion beam generation from circularly polarized laser-pulse interaction with a double-layer target is considered. The front layer consists of heavy-ion plasma, and the rear layer is a small thin coating of light-ion plasma. Particle-in-cell simulation shows that the multi-dimensional effects in the ion radiation pressure acceleration are avoided and a highly monoenergetic light-ion beam can be produced. Our simulations reveal that the charge-mass ratio of heavy ions in the front layer and the thicknesses of both layers can strongly affect the proton energy spectra.

A two-dimensional (2D) multigroup radiation transfer hydrodynamics code LARED-R-1 is used to simulate a supersonic wave experiment performed earlier by the Livermore group. The main result is that, contrary to the conclusion of Back et al. (2000a), the average-atom opacity model is sufficient to explain the obtained experimental results, provided that an adequate description of the radiation transport was used. The simulation results from LARED-R-1 show the spectrum of radiation in foam with radius and length of several optical depths is not in Planckian distribution and the angular intensity distribution is anisotropic.

K α X-ray sources generated from the interaction of ultra-short laser pulses with solids are compact and low-cost source of ultra-short quasi-monochromatic X-rays compared with synchrotron radiation source. Development of collimated ultra-short K α X-ray source by the interaction of 45 fs Ti:sapphire laser pulse with Cu wire target is presented in this paper. A study of the K α source with laser parameters such as energy and pulse duration was carried out. The observed K α X-ray photon flux was ~2.7 × 108 photons/shot at the laser intensity of ~2.8 × 1017 W cm−2. A model was developed to analyze the observed results. The K α radiation was coupled to a polycapillary collimator to generate a collimated low divergence (0.8 mrad) X-ray beam. Such sources are useful for time-resolved X-ray diffraction and imaging studies.

Technique of a linear transformer allows now to build the generators of high power nanosecond pulses with the current rise time of ~100 ns without intermediate power compression stages. This technique is being examined for use in high current high voltage pulsed accelerators. Plasma-filled diode has several advantages over standard vacuum diode that allow to improve the accelerators parameters. In this paper, plasma-filled diode experiments are described on generation of e-beam in the linear transformer accelerator. Possibility of use in the diode of isolated parallel plasma channels has been proven for the e-beam generation with cross-sectional area up to 50 cm2. The beam with current of 100 kA at voltage more than 400 kV was generated in the plasma-filled diode. Energy transmission efficiency from primary storage into a beam is about 54%.