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

Supersonic plasma turbulence in the laboratory

Nature Communications Nature Research 10 (2019) 1758

Authors:

TG White, MT Oliver, P Mabey, AFA Bott, AA Schekochihin, Gianluca Gregori

Low-density hydrodynamic optical-field-ionized plasma channels generated with an axicon lens

PHYSICAL REVIEW ACCELERATORS AND BEAMS 22:4 (2019) ARTN 041302

Authors:

RJ Shalloo, C Arran, A Picksley, A von Boetticher, L Corner, J Holloway, G Hine, J Jonnerby, HM Milchberg, C Thornton, R Walczak, SM Hooker

Erratum: Emittance Preservation in an Aberration-Free Active Plasma Lens [Phys. Rev. Lett. 121, 194801 (2018)].

Physical review letters 122:12 (2019) 129901-129901

Authors:

CA Lindstrøm, E Adli, G Boyle, R Corsini, AE Dyson, W Farabolini, SM Hooker, M Meisel, J Osterhoff, J-H Röckemann, L Schaper, KN Sjobak

Abstract:

This corrects the article DOI: 10.1103/PhysRevLett.121.194801.

Plasma Wakefield Accelerator Research 2019 - 2040: A community-driven UK roadmap compiled by the Plasma Wakefield Accelerator Steering Committee (PWASC)

(2019)

Authors:

Bernhard Hidding, Simon Hooker, Steven Jamison, Bruno Muratori, Christopher Murphy, Zulfikar Najmudin, Rajeev Pattathil, Gianluca Sarri, Matthew Streeter, Carsten Welsch, Matthew Wing, Guoxing Xia

Abstract:

The acceleration gradients generated in a laser- or beam-driven plasma wakefield accelerator are typically three orders of magnitude greater than those produced by a conventional accelerator, and hence plasma accelerators can open a route to a new generation of very compact machines. In addition, plasma-based accelerators can generate beams with unique properties, such as tens of kiloamp peak currents, attosecond bunch duration, ultrahigh brightness and intrinsic particle beam-laser pulse synchronization. In this roadmap we review the status of plasma accelerator research in the UK. We outline potential applications, describe the research and development required to enable those applications, and discuss synergies with related areas of research. We also set-out the resources required to realise these ambitions and provide a timeline for advances in the key areas.

Recovery of metastable dense Bi synthesized by shock compression

Applied Physics Letters AIP Publishing 114:12 (2019) 120601

Authors:

Gorman, David McGonegle, Justin Wark

Abstract:

X-ray free electron laser (XFEL) sources have revolutionized our capability to study ultrafast material behavior. Using an XFEL, we revisit the structural dynamics of shock compressed bismuth, resolving the transition sequence on shock release in unprecedented details. Unlike previous studies that found the phase-transition sequence on shock release to largely adhere to the equilibrium phase diagram (i.e., Bi-V → Bi-III → Bi-II → Bi-I), our results clearly reveal previously unseen, non-equilibrium behavior at these conditions. On pressure release from the Bi-V phase at 5 GPa, the Bi-III phase is not formed but rather a new metastable form of Bi. This new phase transforms into the Bi-II phase which in turn transforms into a phase of Bi which is not observed on compression. We determine this phase to be isostructural with β-Sn and recover it to ambient pressure where it exists for 20 ns before transforming back to the Bi-I phase. The structural relationship between the tetragonal β-Sn phase and the Bi-II phase (from which it forms) is discussed. Our results show the effect that rapid compression rates can have on the phase selection in a transforming material and show great promise for recovering high-pressure polymorphs with novel material properties in the future.

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