Postdoctoral research positions
We do not currently have any postdoctoral research opportunities
The following provide examples of the range of PhD projects available at the John Adams Institute at Imperial College. Please contact us for more information about specific projects:
Relativistic laser-plasma interaction experiments
Supervisor: Prof. Zulfikar Najmudin
In recent years the intensities available at the focus of state of the art lasers has risen to unprecedented levels, such that "table-top" lasers are able to reach intensites of 1019 Wcm-2 and large installations such as the Vulcan Petawatt laser (at the Rutherford Appleton Central Laser Facility) are able to achieve intensities in excess of 1021 Wcm-2.
The potential energy of electrons oscillating in the electric field of these laser pulses at focus is greater than the rest mass energy of the electron and hence their motion becomes extremely relativistic. Furthermore these energies become comparable to nuclear binding energy. Hence these interactions can be characterised by extremely non-linear interaction, generation of particle beams to high energy, creation of exotic states of matters and huge electric and magnetic fields. Recent highlights have included the first demonstration of laser acceleration of electron beams in a narrow energy range, measurement of the largest magnetic fields generated in the laboratory (in excess of 40,000 T!) and generation of high-quality proton beams which may have applications in radiography and proton therapy of cancer tumours.
The area thus has potential for the exploration of a wealth of novel complex physical phenomena, and is an ideal one for PhD projects since it allows the whole range of input in the process of physical investigation including planning, experimentation, analysis and modelling. Much of the work is performed in a team, with the opportunity to work on a variety of experiments and learn many different experimental techniques. As a result, there is considerable scope for a student to find their own particular interests and determine the path of their research.
Femtosecond x-ray probing of high-energy-density physics experiments using plasma wiggler radiation
The bright x-rays produced due to transverse (or “betatron”) oscillations of the electron beam in a self-injecting laser wakefield accelerator [Mangles, Nature 2004; Kneip, Nature Phys 2010] have a unique combination of properties namely small source size, ultra-short duration and broad spectral coverage. These properties make them ideal for studying high-energy-density matter.
Project 1: Femtosecond x-ray probing of plasma opacity
Supervisor: Stuart Mangles
In this project you will develop experiments to make ultra-fast time resolved measurements that use the unique capabilities of this “plasma wiggler radiation”. The broad spectrum of the plasma wiggler radiation, combined with its ultra-short (femtosecond) duration will be used to provide an ideal white-light source for unprecedented time resolved measurements of the opacity of rapidly-heated plasmas. Such measurements will help to develop models of the opacity of high-energy-density matter, which are vital for our understanding of, for example the structure and evolution of the Sun. These models could be tested robustly over a broad parameter space by examining the heating of matter using “conventional” laser heating using facilities such as the Cerberus laser here at Imperial college and the Astra Gemini Laser at the Rutherford Appleton Laboratory, and by heating matter so that it is far from equilibrium using international x-ray free electron lasers such as the LCLS.
Project 2: Ultra-fast Imaging of Shocks “on-the-fly”
The small, micrometre scale source size of plasma wiggler [Kneip Nature Phys 2010] means it can perform high-resolution x-ray phase contrast imaging [Kneip Applied Phys Lett 2011]. Combining this impressive imaging capability with the ultra-short duration of the x-rays will make it possible to perform time resolved imaging of laser-induced shocks in solid material, this will allow you to image shocks “on the fly”.
Third generation synchrotron light sources have recently been used to provide single-shot x-ray phase contrast imaging of dynamic shocks on the fly, however they are limited to temporal resolution of ~ 100 ps. In this project you will develop experiments to perform similar measurements but with unprecedented < 100 fs resolution – an improvement of a factor of more than 1 million. Such ultra-fast resolution will permit the observation of rapid phase transitions in shocked materials and allow detailed studies of the equation of state.