Features of the electrical current in an x-ray source based on a vacuum diode with a laser-plasma cathode

Instabilities of the discharge, as well as temporal and energetic characteristics of x-ray radiation a source based on the vacuum diode with laser-plasma cathode in a wide range of energies, power densities, duration of plasma forming laser pulse, have been experimentally studied. It has been observed that the characteristics of laser radiation significantly affect the dynamics of vacuum discharge and allow to control radiation processes at the early stages of its development. The minimum recorded duration of x-ray pulse (with photon number 1011 per pulse) in titanium K-shells (~4.5 keV) was 10 ns in the case of generation of plasma cathode using laser radiation with the duration of 27 ps and intensity ~1013 W/cm2. It has been established that in the regime of instability suppression and at the application of accelerating voltage (about 3 - 4 times the excitation threshold), the maximum value of contrast of characteristic radiation over Bremsstrahlung is achieved.