PhD opportunities

Novel particle acceleration based on laser wakefield accelerators

Title 
Novel particle acceleration based on laser wakefield accelerators
Supervisor
Professor  Zulfikar Najmudin
 Type
 Experimental (may include simulational work)
 Description  

Laser wakefield accelerators are being investigated for the next generation of particle accelerators. A high intensity laser pulse generates a large amplitude plasma wave, which can accelerate particles at a rate more than thousands of times faster than conventional accelerators. Acceleration of electrons sourced directly from the plasma is now well established with wakefield accelerators. However, the beams produced are not yet of the quality required for the high energy physics applications.  This project will investigate novel techniques to improve the beam quality from laser wakefield accelerators including structuring of targets and staged acceleration. The work will be performed using the high-power lasers at the Rutherford-Appleton Laboratory as well as with the laser being developed in the basement of the Blackett Laboratory

Funding JAI studentship

Radiation pressure effects at the focus of intense lasers

Title 
Radiation pressure effects at the focus of intense lasers
Supervisor
Professor  Zulfikar Najmudin
 Type
 Experimental (may include simulational work)
 Description  

State-of-the-art lasers can now reach intensities well in excess of 1020 Wcm-2 at focus. When directed onto a target that is sufficiently dense that it can stop the laser beam, the intense radiation pressure can directly drive the critical density surface of the target. This can manifest itself in a number of ways. It can drive a collisionless shocks which can be diagnosed by the ions it accelerates in its path. Alternatively, for sufficiently thin targets, the whole plasma can be propelled forward gaining momentum as it propagates. The result in both cases is the production of dense beams of energetic ions. These ions could have numerous applications, not least in next-generation particle accelerators. The project proposed here will investigate radiation pressure driven acceleration schemes through optimisation of targets and of the characteristics of the laser beam that drives them. The experiments will take place on the high intensity lasers at the Rutherford-Appleton Laboratory and the IR laser at the ATF Brookhaven National Laboratory. A near term goal is to produce protons with energies exceeding 100 MeV, which would be of interest for applications such as radiation treatment of tumours or for fast heating of fusion capsules.

Funding JAI studentship  

Time resolved x-ray absorption studies of Matter in Extreme Conditions

Much of the visible universe exists in extreme conditions, for example at high pressures and  temperatures inside stars and gas giant planets or in the presence of intense xray fluxes (eg the low density gas near black holes).   Much of our understanding of these systems comes from detailed atomic physics calculations.  However testing these models experimentally is very challenging -- such extreme conditions can now be created in the lab but only for very short periods of time (~ 1ps).

One of the ideal ways to study the atomic physics of these highly transient lab systems under extreme conditions is to use X-ray absorption spectroscopy, and the ideal X-ray source would have a broad spectrum (to allow absorption features to be observed) and femtosecond duration (to freeze the transient behaviour).  Our group has pioneered the development of X-ray radiation from laser wakefield accelerators which uniquely has both these properties. As part of the TeX-MEx project,  funded by the ERC, we have have a fully funded PhD position available in 2017. 

We are recruiting a student  to  join our experimental team.  You will be involved in developing our X-ray absorption spectroscopy program, designing, running and analysing experiments at national and international facilities such as the Astra Gemini laser at the Rutherford laboratory and X-ray free electron lasers. These experiments will use the unique properties of betatron radiation to probe the ultrafast dynamics of some of the most extreme conditions in the universe.

For more information please contact Stuart Mangles.