Turbulent Richtmyer-Meshkov instability (RMI) is investigated through a series of high resolution three dimensional smulations of two initial conditions with eight independent codes. The simulations are initialised with a narrowband perturbation such that instability growth is due to non-linear coupling/backscatter from the energetic modes, thus generating the lowest expected growth rate from a pure RMI. By independently assessing the results from each algorithm, and computing ensemble averages of multiple algorithms, the results allow a quantification of key flow properties as well as the uncertainty due to differing numerical approaches. A new analytical model predicting the initial layer growth for a multimode narrowband perturbation is presented, along with two models for the linear and non-linear regime combined. Overall, the growth rate exponent is determined as θ = 0.292 ± 0.009, in good agreement with prior studies; however, the exponent is decaying slowly in time. Also, θ is shown to be relatively insensitive to the choice of mixing layer width measurement. The asymptotic integral molecular mixing measures Θ = 0.792 ± 0.014, Ξ = 0.800±0.014 and Ψ = 0.782±0.013 which are lower than some experimental measurements but within the range of prior numerical studies. The flow field is shown to be persistently anisotropic for all algorithms, at the latest time having between 49% and 66% higher kinetic energy in the shock parallel direction compared to perpendicular and does not show any return to isotropy. The plane averaged volume fraction profiles at different time instants collapse reasonably well when scaled by the integral width, implying that the layer can be described by a single length scale and thus a single θ. Quantitative data given for both ensemble averages and individual algorithms provide useful benchmark results for future research.

The heating of inertial confinement fusion (ICF) target by fast electrons, which are generated as a result of laser interaction with expanding plasma (corona) of a target, is investigated theoretically. It is shown that due to remoteness of the peripheral region, where electrons are accelerated, a significant portion of these particles, moving in corona and repeatedly crossing it due to reflection in a self-consistent electric field, will not hit into the compressed part of target. Using the modern models of fast electron generation, it is shown that in a typical target designed for spark ignition, the fraction of fast electrons that can pass their energy to compressed part of target is enough small. Only 12% of the total number of fast electrons can do it. Such an effect of "wandering" of fast electrons in corona leads to a significant decrease in a negative effect of fast electrons on target compression. Taking into account the wandering effect, the distribution of energy transmitted by fast electrons to different parts of target and the resulting reduction of deuterium-tritium (DT) fuel compression are established.

In impact ignition, the compressed deuterium–tritium main fuel is ignited by impact with a separately imploded portion of fuel, which is accelerated in a hollow conical target to hyperspeeds of the order of 1000 km s−1. Its kinetic energy is directly converted into thermal energy corresponding to an ignition temperature of about 5 keV upon collision with the compressed fuel. The ignitor shell is irradiated by nanosecond pulses at intensities of between 1015 and 1016 W cm−2 with a wavelength of 0.25–0.35 µm, resulting in ablation pressures of several hundred mega-bars. Hydrodynamics-dominated physics and avoidance of ultra-intense petawatt lasers are notable features of this scheme. Experimental results for velocities exceeding 1000 km s−1, ion temperatures up to 3 keV, and neutron yield increases of 100-fold due to the impact effect indicate the potential of impact ignition for fusion energy production. The overall performance of impact ignition is reviewed with new analyses on the neutron yield and shell acceleration.

Reduction of the fast electron angular dispersion by means of varying-resistivity structured targets Phys. Plasmas 20, 013109 (2013) Nuclear stopping power in warm and hot dense matter Phys. Plasmas 20, 012705 (2013) Threshold conditions for lasing of a free electron laser oscillator with longitudinal electrostatic wiggler Phys. Plasmas 19, 123106 (2012) Halo formation and self-pinching of an electron beam undergoing the Weibel instability Phys. Plasmas 19, 103106 (2012) Additional information on Phys. Plasmas Proton bursts with a narrow spectrum at an energy of (2.8 6 0.3 MeV) are accelerated from sub-micron water spray droplets irradiated by high-intensity ($5 Â 10 19 W/cm 2 ), high-contrast ($10 10 ), ultra-short (40 fs) laser pulses. The acceleration is preferentially in the laser propagation direction. The explosion dynamics is governed by a residual ps-scale laser pulse pedestal which "mildly" preheats the droplet and changes its density profile before the arrival of the high intensity laser pulse peak. As a result, the energetic electrons extracted from the modified target by the highintensity part of the laser pulse establish an anisotropic electrostatic field which results in anisotropic Coulomb explosion and proton acceleration predominantly in the forward direction. Hydrodynamic simulations of the target pre-expansion and 3D particle-in-cell simulations of the measured energy and anisotropy of the proton emission have confirmed the proposed acceleration scenario. V C 2012 American Institute of Physics. [http://dx

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