Figure 1. Scheme of generation of ultra-intense X-ray source in relativistic laser-produced plasma.

Relativistic laser beam focuses on the foil (central Zone) and generates very intense bunches of fast electrons, which, due to strong refluxing in the expanded plasma, produce ultra-bright X-rays with a duration comparable to the laser pulse duration or slightly longer. Such transient RDKR X-ray source heats periphery of plasma up to hundreds eV temperature keeping it solid (Zone 1). At a greater distance from the center of the plasma (Zones 2 and 3) electron temperature drops to a few eV, and due to efficient pumping by X-ray source hollow ions are generated there. Plasma radiated by Zones 1–3 are measured by X-ray spectrometer.