Prof Peter Norreys FInstP;: Publications

Infinite dimensional optimistic optimisation with applications on physical systems

(2016)

Authors:

Muhammad F Kasim, Peter A Norreys

Essential criteria for efficient pulse amplification via Raman and Brillouin scattering

(2016)

Authors:

RMGM Trines, EP Alves, E Webb, J Vieira, F Fiuza, RA Fonseca, LO Silva, J Sadler, N Ratan, L Ceurvorst, MF Kasim, M Tabak, D Froula, D Haberberger, PA Norreys, RA Cairns, R Bingham

High orbital angular momentum harmonic generation

(2016)

Authors:

J Vieira, RMGM Trines, EP Alves, RA Fonseca, JT Mendonça, R Bingham, P Norreys, LO Silva

Scaled laboratory experiments explain the kink behaviour of the Crab Nebula jet

Nature Communications Nature Publishing Group (2016)

Authors:

CK Li, P Tzeferacos, D Lamb, Gianluca Gregori, PA Norreys, MJ Rosenberg, RK Follett, DH Froula, M Koenig, FH Seguin, JA Frenje, HG Rinderknecht, H Sio, AB Zylstra, RD Petrasso, PA Amendt, HS Park, BA Remington, DD Ryutov, SC Wilks, R Betti, A Frank, SX Hu, TC Sangster, P Hartigan

Abstract:

The remarkable discovery by the Chandra X-ray observatory that the Crab nebula's jet periodically changes direction provides a challenge to our understanding of astrophysical jet dynamics. It has been suggested that this phenomenon may be the consequence of magnetic fields and magnetohydrodynamic instabilities, but experimental demonstration in a controlled laboratory environment has remained elusive. Here we report experiments that use high-power lasers to create a plasma jet that can be directly compared with the Crab jet through well-defined physical scaling laws. The jet generates its own embedded toroidal magnetic fields; as it moves, plasma instabilities result in multiple deflections of the propagation direction, mimicking the kink behaviour of the Crab jet. The experiment is modelled with three-dimensional numerical simulations that show exactly how the instability develops and results in changes of direction of the jet.

Numerical study of neutron beam divergence in a beam-fusion scenario employing laser driven ions

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Elsevier 829 (2016) 176-180

Authors:

A Alejo, A Green, H Ahmed, APL Robinson, M Cerchez, R Clarke, D Doria, S Dorkings, J Fernandez, P McKenna, SR Mirfayzi, K Naughton, D Neely, Peter Norreys, C Peth, H Powell, JA Ruiz, J Swain, O Willi, M Borghesi, S Kar

Abstract:

The most established route to create a laser-based neutron source is by employing laser accelerated, low atomic-number ions in fusion reactions. In addition to the high reaction cross-sections at moderate energies of the projectile ions, the anisotropy in neutron emission is another important feature of beam-fusion reactions. Using a simple numerical model based on neutron generation in a pitcher–catcher scenario, anisotropy in neutron emission was studied for the deuterium–deuterium fusion reaction. Simulation results are consistent with the narrow-divergence (∼70° full width at half maximum) neutron beam recently served in an experiment employing multi-MeV deuteron beams of narrow divergence (up to 30° FWHM, depending on the ion energy) accelerated by a sub-petawatt laser pulse from thin deuterated plastic foils via the Target Normal Sheath Acceleration mechanism. By varying the input ion beam parameters, simulations show that a further improvement in the neutron beam directionality (i.e. reduction in the beam divergence) can be obtained by increasing the projectile ion beam temperature and cut-off energy, as expected from interactions employing higher power lasers at upcoming facilities.

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