Lab Astrophysics and High Energy Densities
Creating and probing extreme conditions with high power lasers
- Type: Experimental, with some simulations
High power lasers can be used to create extreme conditions in the laboratory that are usually only found in extreme astrophysical environments. Using short-pulse high power lasers my research group is trying to create matter at temperatures and densities usually only found in the centre of stars and gas giant planets and use ultra-short flashes of X-rays to probe these; we can collide laser accelerated electron beams with high power lasers to measure the effects of very strong electromagnetic fields that can occur on the surface of quasars; and we are attempting to make X-ray fields that are so dense that photon-photon collisions, producing matter out of pure energy, something that can occur with intense gamma ray beams produced by massive compact objects. By recreating and characterising such extreme conditions in the laboratory, we hope to increase our understanding of extreme astrophysical environments.
- Funding: 3,5 years fully funded via ERC grant (Home/EU students only)
For more information please contact Stuart Mangles.
Laboratory Astrophysics and High Energy Density Physics
PhD projects for academic year 2020 - 2021 (subject to funding, see below)
Type: Experimental, including target and experiment design, and some simulations
High-Energy Density (HED) deals with matter at extreme states of density, temperature and pressure, very rarely encountered on Earth but very common in astrophysical phenomena. At these extreme conditions matter is usually in the ‘plasma’ state, a hot, ionised gas made of charged particles mediated by their electromagnetic fields. The ability to produce (and most importantly systematically reproduce) such plasmas on Earth-based laboratories has grown substantially thanks to technological advances in experimental plasma facilities such as high-power lasers and pulsed-power magnetic-field drivers. The combination of HED and laboratory experiments is the core of my research in ‘High Energy Density Laboratory Astrophysics’ (HEDLA), a cross-disciplinary area aimed at studying different aspects of space and astrophysical environments by the means of Earth-based laboratory experiments.
PhD project 1: Radiative shocks in high-power laser experiments
This PhD project will involve the design and performance of laboratory experiments in world class, high-power laser systems to study the formation of ‘radiative shocks’, shocks in which the main plasma parameters such as pressure, density and temperature are drastically modified by strong radiative losses, which only occur at shock speeds ~10-100s km/s. The project will involve learning about the physics at play, design of the experiments and targets (typically miniaturised gas-filled cells), use of different plasma diagnostics (e.g. X-ray backlighting imaging, optical emission imaging and spectroscopy) and the possibility of modelling these shocks with radiation hydrodynamics codes.
- T. Clayson et al., ‘Counter-propagating radiative shock experiments on the Orion laser and the formation of radiative precursors’, High-Energy Density Physics vol. 23: 60-72 (2017)
- R.P. Drake et al., ‘Radiative shocks in astrophysics and the laboratory’, Astrophysics & Space Science vol. 298: 49-59 (2005).
PhD project 2: Supersonic jets in pulsed-power experiments
This PhD project will involve laboratory experiments on the in-house MAGPIE (Mega Ampere Generator for Plasma Implosion Experiments) facility. MAGPIE is based in the Blackett Laboratory, Imperial College London, and is the largest pulsed-power facility in a University environment. The aim is to study the formation of jets launched and collimated by the magnetic fields produced by the extreme electrical current generated on MAGPIE. The project will look, for instance, at the formation of shocks from the counterpropagating collision between two jets (using a ‘radial foil’ setup), and the acceleration of charged particles from a single magnetised jet (using a ‘radial wire array’ setup).
- F. Suzuki-Vidal et al., ‘Bow Shock Fragmentation Driven by a Thermal Instability in Laboratory Astrophysics Experiments’, The Astrophysical Journal 815, 2, p. 96 (2015)
- S.V. Lebedev, A. Frank, D.D. Ryutov, ‘Exploring astrophysics-relevant magnetohydrodynamics with pulsed-power laboratory facilities’, Review of Modern Physics 91, 025002 (2019)
Funding: Both projects are subject to funding (for instance Imperial College President’s Scholarship, Departmental EPSRC DTA, self-funding). We kindly ask potential applicants to check the requirements of each funding scheme before getting in touch.
For more information, please contact Dr Francisco Suzuki-Vidal
Keywords: Experimental plasma physics, high-power lasers, radiation hydrodynamics, plasma diagnostics, target design, numerical simulations
Modelling the effects of radiation and magnetic fields on shocks and turbulent flows in laboratory astrophysics experiments
Shocks and transition to turbulence in magnetized high density plasmas
Type: Experimental, including development of diagnostics
Shock waves are important feature of many magnetised plasmas in astrophysics, in space plasmas and in laboratory plasmas relevant to Inertial Confinement Fusion research. We are recruiting a student to join our experimental team working on the 1.4MA MAGPIE pulsed power facility at Imperial College. The PhD project will be focused on the studies of the shock waves formed in the interaction of supersonic plasma flows with various obstacles. Of particular interest will be investigations of the development of instabilities in the shocks, in conditions scalable to astrophysical shocks. The project could also involve studies of the development of turbulence in rotating plasmas. Work will involve modification of the already existing experimental set-ups, designing appropriate targets allowing quantitative characterisation of the shocks, and designing and testing of new experimental configurations. The project will also involve the development and implementation of advanced plasma diagnostics, such as Thomson scattering, interferometry, optical and x-ray imaging and spectroscopy and X-ray radiography.
G. C. Burdiak et al., Physics of Plasmas 24, 072713 (2017).
J.D. Hare et al., Physical Review Letters 118, p. 085001 (2017)
Funding: Departmental studentship (pending)
Supervisor: Sergey Lebedev