Faster-than-light EMP source initiated by short X-ray pulse of laser plasma

The effect which manifests itself in the form of directed electromagnetic pulses initiated by an X-ray incident obliquely on the conducting surface has been confirmed and investigated experimentally in detail. The existence of the above-mentioned phenomenon was predicted more than 25 years ago. So, experimentally, a planar accelerating diode comprising a metallic cathode and grid anode was initiated by an oblique short soft X-ray pulse from a point laser plasma source. Then, the directed EMP source, i.e., the accelerated photoelectron current, was formed, whose boundary ran along the external surface of the anode at a faster-than-light velocity. The plasma was formed when a short-pulse (∼0.3 ns) laser radiation from ISKRA-5 facility was focused onto a plane Au target. The amplitude-in-time and spatial characteristics of the radiation emitted by the faster-than-light source are measured. The parameters of the photo-emission current and accelerated electron current are measured.