Abstract

    报告人简介：

Dr. Thomas Clayson is currently a scientist at First Light Fusion in the UK, working in the pulsed power team. He completed his PhD at Imperial College London under the supervision of Dr. Francisco Suzuki-Vidal and Prof. Sergey Lebedev. His current research focuses on High-Energy Density Physics (HEDP), Inertial Confinement Fusion (ICF) and pulsed power engineering.

• 13 publications in the journals of Physical Review Letters, High Energy Density Physics, Physics of Plasmas, Journal of Applied Physics and High Power Laser Science and Engineering.
• Presentations at multiple international research conferences including: HEDLA 2016 and APS 2016 in the USA, MEC 2017 in France, ICHED 2017 in Japan and DZP 2017 in the USA.
• Worked as part of international teams during experimental campaigns on the on the Orion Laser Facility in the UK, the Prague Asterix Laser System in the Czech Republic and the ShenGuang II laser facility in China.
• Designed and run experiments to study radiative shocks in gases on the MAGPIE facility (Mega Ampere Generator for Plasma Implosion Experiments) at Imperial College London.

报告摘要：

Magnetically-Driven Radiative Shock Experiments for Laboratory Astrophysics

We present results from new experiments, aimed at producing radiative shocks, using an “inverse liner” configuration on the MAGPIE pulsed power facility (~1.4 MA in 240 ns) [1] at Imperial College London in the UK. These experiments bear many similarities to magnetized liner inertial fusion (MagLIF) [2] and previous converging liner experiments performed on MAGPIE [3], where a large current is passed through a thin walled metal cylinder (liner) filled with gas, causing it to magnetically compress the gas. Our experimental setup uses an “inverse liner” where the liner is surrounded by gas and the inside is vacuumed out. Current is passed through the liner and then returned through a central rod on the axis, generating a strong (~40 Tesla) toroidal magnetic field within the liner. This drives a shock through the liner which in turn drives a cylindrically symmetric, radially expanding radiative shock in to the gas surrounding the liner.

Unlike converging shock experiments, where the dynamics are located within the imploding liner and thus difficult to probe, our experimental setup is much more open for diagnostic access, can be probed from the side and allows shocks to propagate significantly further. Multi-frame optical self-emission imaging, 532 nm and 355 nm laser interferometry, optical emission spectrometry and magnetic probes were used to provide a better understanding of the shock dynamics. Experiments were performed in a variety of different gases (Ne, Ar, Kr, Xe at pressures 1-50 mbar), while maintaining a constant mass density to produce similar shock hydrodynamics. This new configuration for producing radiative shocks provides a unique platform for numerical validation and laboratory astrophysics applications.

[1] I. H. Mitchell et al. “A high impedance mega-ampere generator for fiber z-pinch experiments” Review of Scientific Instruments, 67, 1533-1541 (1996)

[2] M. Gomez et al. “Experimental demonstration of fusion-relevant conditions in magnetized liner inertial fusion” Physical Review Letters, 113, 155003 (2014)

[3] G. Burdiak et al. “Cylindrical liner Z-pinch experiments for fusion research and high-energy density physics” Journal of Plasma Physics, 81(3), 365810301 (2015)