Simulating intense x-ray production in laser-matter interactions

The interaction of high-intensity lasers with matter provides an extremely bright source of x-rays, with potential application to medical imaging and national security. In this project the student will investigate the use of these x-rays to generate exotic states of matter. At current laser intensities (~10^20W/cm^2) the x-ray emission is at the right energy (several keV) to liberate inner shell electrons from atoms and create matter dominated by exotic ‘hollow atoms’. The energy of the x-ray photons increases to the MeV level when the laser interacts with a high atomic number target (e.g. gold). These x-ray photons can decay to electron-positron pairs in the target, generating dense electron-positron plasmas. The laboratory study of these plasmas gives insight into plasma instabilities operating in extreme astrophysical environments (such as pulsar magnetospheres). As the laser intensity increases to that available at the soon to be operational Extreme Light Infrastructure (~10^23W/cm^2) it is unknown how the generated x-rays interact with the material of the target. Prolific generation of exotic particles (muons, pions) is possible, as is the pumping of exotic nuclear states.

The project will involve performing numerical simulations using state of the art plasma physics and particle/nuclear physics codes and the development of analytical theory (for example, scaling laws for the emitted x-ray photon energy in a given interaction). It is envisaged that the student will work closely with experimentalists to design experiments to observe the predicted exotic matter.