Two-Dimensional Time-Resolved Ultra-High Speed Imaging Of K-Alpha Emission From Short-Pulse-Laser Interactions To Observe Electron Recirculation

Time resolved x-ray images with 7 ps resolution are recorded on relativistic short-pulse laser-plasma experiments using the dilation x-ray imager, a high-speed x-ray framing camera, sensitive to x-rays in the range of approximate to 1 - 17 keV. This capability enables a series of 2D x-ray images to be recorded at picosecond scales, which allows for the investigation of fast electron transport within the target with unprecedented temporal resolution. An increase in the Ka-emission spot size over time was found for targets thinner than the recirculation limit and is absent for thicker targets. Together with the observed polarization dependence of the spot size increase, this indicates that electron recirculation is relevant for the x-ray production in thin targets. Published by AIP Publishing.