Influence of laser-drive parameters on annular fast electron transport in silicon

Three-dimensional hybrid particle-in-cell simulations are used to investigate the sensitivity of annular fast electron transport patterns in silicon to the properties of the drive laser pulse. It is found that the annular transport, which is induced by self-generated resistive magnetic fields, is particularly sensitive to the peak laser pulse intensity. The radius of the annular fast electron distribution can be varied by changing the drive laser pulse properties, and in particular the focal spot size. An ability to optically 'tune' the properties of an annular fast electron transport pattern could have important implications for the development of advanced ignition schemes and for tailoring the properties of beams of laser-accelerated ions.