Oxford Centre for High Energy Density Science (OxCHEDS): publications

Measurement of the electron-density profile in a discharge-ablated capillary waveguide

Optics Letters 24:14 (1999) 993-995

Authors:

DJ Spence, PDS Burnett, SM Hooker

Abstract:

Discharged-ablated capillary waveguides were investigated based on electron-density profile using time-resolved interferometric measurements. A pronounced axial minimum with a relative depth of as much as 60% of the axial electron density was developed in the electron density profile. Results showed that this profile can be used for high-intensity laser pulse tunneling.

A spectroscopic analysis of near solid density plasmas

Laser and Particle Beams Cambridge University Press (CUP) 17:3 (1999) 477-485

Authors:

R SMITH, GJ TALLENTS, SJ PESTEHE, G HIRST, J LIN, S ROSE, M TAGVIASHVILI

Observation of a highly directional γ-ray beam from ultrashort, ultraintense laser pulse interactions with solids

Physics of Plasmas AIP Publishing 6:5 (1999) 2150-2156

Authors:

PA Norreys, M Santala, E Clark, M Zepf, I Watts, FN Beg, K Krushelnick, M Tatarakis, AE Dangor, X Fang, P Graham, T McCanny, RP Singhal, KWD Ledingham, A Creswell, DCW Sanderson, J Magill, A Machacek, JS Wark, R Allott, B Kennedy, D Neely

Abstract:

Novel measurements of electromagnetic radiation above 10 MeV are presented for ultra intense laser pulse interactions with solids. A bright, highly directional source of γ rays was observed directly behind the target. The γ rays were produced by bremsstrahlung radiation from energetic electrons generated during the interaction. They were measured using the photoneutron reaction [63Cu(γ,n)62Cu] in copper. The resulting activity was measured by coincidence counting the positron annihilation γ rays which were produced from the decay of Cu62. New measurements of the bremsstrahlung radiation at 1019 W cm−2 are also presented.

Table-top picosecond sources

Nature Springer Nature 398:6725 (1999) 284-285

Studies of the fast ignition route to inertial confinement fusion at the Rutherford Appleton Laboratory

FUSION ENG DES 44 (1999) 239-243

Authors:

PA Norreys, M Bakarezos, L Barringer, M Borghesi, FN Beg, M Castro-Colins, D Chambers, AE Dangor, CN Danson, A Djaoui, AP Fews, R Galliard, P Gibbon, L Gizzi, ME Glinsky, BA Hammel, MH Key, P Lee, P Loukakos, AJ MacKinnon, C Meyer, J Meyer-ter-Vehn, S Moustaizis, SG Preston, A Pukhov, SJ Rose, M Tatarakis, JS Wark, O Willi, M Zepf, J Zhang

Abstract:

The Rutherford Appleton Laboratory has been at the forefront of investigations into the physics associated with the fast ignition concept for inertial confinement fusion. This scheme involves complex laser-plasma processes, the theoretical understanding of which relies heavily on particle-in-cell calculations. In this paper, three experiments displaying quantitative agreement with detailed multi-dimensional PIC calculations are reviewed: hole-boring velocity measurements; relativistic self-focusing; and harmonic generation from plasma surfaces. Qualitative agreement of hot electron temperature measurements with PIC simulations are also discussed. The authors believe these results are very encouraging for the fast ignition concept. (C) 1999 Published by Elsevier Science S.A. All rights reserved.

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