Oxford Centre for High Energy Density Science (OxCHEDS)

Abstract:

The interaction of high intensity laser pulses with plasmas is an efficient source of megaelectronvolt ions. Recent observations of the production of directional energetic ion 'beams' from the front and rear surfaces of thin foil targets upon irradiation by intense laser pulses have prompted a renewed interest into research in this area. In addition, other recent observations have shown that high energy ions can be observed from intense laser interaction with low density plasma as a result of ponderomotive shock acceleration. The source characteristics and acceleration mechanisms for these ions have been extensively investigated, and there have also been a number of proposed applications for these ion beams, such as for injectors into subsequent conventional acceleration stages, for medicine, for probing of dense plasmas and for inertial confinement fusion experiments. © 2005 IOP Publishing Ltd.

Abstract:

Our team has provided the first observations of energetic ion beam production from the front and rear surfaces thin foil targets upon irradiation by an intense laser beam in the relativistic regime. We invented a new plasma diagnostic technique in which "layered" track detectors and dosimetry media were used to simultaneously record ion angular emission patterns as well as ion spectral information. These results have led to a large number of further experiments in which similar measurement techniques were used and in which protons have been measured up to 58 MeV. The source and acceleration mechanisms for these proton beams have been extensively investigated. There have also been a number of proposed applications for these ion beams, such as for injectors into subsequent conventional acceleration stages, for probing of dense plasmas and for inertial confinement fusion experiments. © 2005 IEEE.

Abstract:

We review a recent experimental campaign to study the interaction physics of petawatt laser pulses incident at relativistic intensities on solid targets. The campaign was performed on the 500 J sub-picosecond petawatt laser at the Rutherford Appleton Laboratory. An extensive suite of optical, x-ray, and particle diagnostics was employed to characterise the processes of laser absorption, electron generation and transport, thermal and K-alpha x-ray generation, and proton acceleration.