There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Recent years have witnessed many breakthroughs in research on graphene (the first two-dimensional atomic crystal) as well as a significant advance in the mass production of this material. This one-atom-thick fabric of carbon uniquely combines extreme mechanical strength, exceptionally high electronic and thermal conductivities, impermeability to gases, as well as many other supreme properties, all of which make it highly attractive for numerous applications. Here we review recent progress in graphene research and in the development of production methods, and critically analyse the feasibility of various graphene applications.

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A roadmap for graphene

QUANTUM gravitational effects are usually ignored in calculations of the formation and evolution of black holes. The justification for this is that the radius of curvature of space-time outside the event horizon is very large compared to the Planck length (Għ/c3)1/2 ≈ 10−33 cm, the length scale on which quantum fluctuations of the metric are expected to be of order unity. This means that the energy density of particles created by the gravitational field is small compared to the space-time curvature. Even though quantum effects may be small locally, they may still, however, add up to produce a significant effect over the lifetime of the Universe ≈ 1017 s which is very long compared to the Planck time ≈ 10−43 s. The purpose of this letter is to show that this indeed may be the case: it seems that any black hole will create and emit particles such as neutrinos or photons at just the rate that one would expect if the black hole was a body with a temperature of (κ/2π) (ħ/2k) ≈ 10−6 (M/M)K where κ is the surface gravity of the black hole1. As a black hole emits this thermal radiation one would expect it to lose mass. This in turn would increase the surface gravity and so increase the rate of emission. The black hole would therefore have a finite life of the order of 1071 (M/M)−3 s. For a black hole of solar mass this is much longer than the age of the Universe. There might, however, be much smaller black holes which were formed by fluctuations in the early Universe2. Any such black hole of mass less than 1015 g would have evaporated by now. Near the end of its life the rate of emission would be very high and about 1030 erg would be released in the last 0.1 s. This is a fairly small explosion by astronomical standards but it is equivalent to about 1 million 1 Mton hydrogen bombs. It is often said that nothing can escape from a black hole. But in 1974, Stephen Hawking realized that, owing to quantum effects, black holes should emit particles with a thermal distribution of energies — as if the black hole had a temperature inversely proportional to its mass. In addition to putting black-hole thermodynamics on a firmer footing, this discovery led Hawking to postulate 'black hole explosions', as primordial black holes end their lives in an accelerating release of energy.

Black Hole Explosions

Terahertz spectroscopy systems use far-infrared radiation to extract molecular spectral information in an otherwise inaccessible portion of the electromagnetic spectrum. Materials research is an essential component of modern terahertz systems: novel, higher-power terahertz sources rely heavily on new materials such as quantum cascade structures. At the same time, terahertz spectroscopy and imaging provide a powerful tool for the characterization of a broad range of materials, including semiconductors and biomolecules.

Materials for terahertz science and technology

Fusion energy from reacting hydrogen (protons) with the boron isotope 11 (HB11) resulting in three stable helium nuclei, is without problem of nuclear radiation in contrast to DT fusion. But the HB11 reaction driven by nanosecond laser pulses with thermal compression and ignition by lasers is extremely difficult. This changed radically when irradiation with picosecond laser pulses produces a non-thermal plasma block ignition with ultrahigh acceleration. This uses the nonlinear (ponderomotive) force to surprisingly resulting in same thresholds as DT fusion even under pessimistic assumption of binary reactions. After evaluation of reactions trapped cylindrically by kilotesla magnetic fields and using the measured highly increased HB11 fusion gains for the proof of an avalanche of the three alphas in secondary reactions, possibilities for an absolutely clean energy source at competitive costs were concluded.

Picosecond-petawatt laser-block ignition of avalanche boron fusion by ultrahigh acceleration and ultrahigh magnetic fields

Spectroscopic diagnostics of ionization balance and electron density in ultrashort plasmas.

A high energy flashlamp pumped Ti:sapphire laser has been developed for the pumping source of Yb:glass chirped pulse amplification. The free running oscillator generates 12 Joule/pulse at 793 nm at 1 Hz repetition. The output energy of 6 Joule/pulse at 920 nm has been obtained.

High-energy flash-lamp-pumped Ti-sapphire laser for Yb:glass CPA

In our design of Petawatt scale Ti:sapphire laser ("Hercules") a pump laser based on high average power glass (QX-ND, Kigre, Inc) is used at the 100 TW stage. This pump laser generates 14 J of a frequency doubled output at 0.1 Hz repetition rate in 80 ns pulse. In this paper we present a design of a relatively simple and inexpensive extension of this laser allowing to generate pump energy 60-80 J, necessary to reach Petawatt powers. The pump laser consists of a Nd:YLF oscillator, a preamplifier and two 2-pass glass amplifiers with 16-mm diameter phosphate glass rods.

Development of Petawatt scale Ti:sapphire laser at 0.05 Hz repetition rate

An analytical model and numerical simulations demonstrate that pulses with intensities exceeding 1022 W/cm2 may penetrate deeply into the plasma and accelerate efficiently ions in the forward direction. We propose a new scheme for fast ignition of precompressed DT fusion targets by using two laser pulses. The first pulse (or a sequence of several pulses) creates a channel with diameter ~ 30μm through the plasma corona up to the fuel density ~ 1 g/cm3. The second pulse with a higher intensity accelerates the deuterium and tritium ions at the head of this channel. The overall ignition energy is ~ 100 kJ.

http://robots.iopscience.iop.org/article/10.1088/1742-6596/244/2/022069/pdf

Gerard Mourou

Papers

Picosecond-petawatt laser-block ignition of avalanche boron fusion by ultrahigh acceleration and ultrahigh magnetic fields

Spectroscopic diagnostics of ionization balance and electron density in ultrashort plasmas.

High-energy flash-lamp-pumped Ti-sapphire laser for Yb:glass CPA

Development of Petawatt scale Ti:sapphire laser at 0.05 Hz repetition rate

Relativistic hole boring and fast ion ignition with ultra-intense laser pulses