Copper vapour laser pumped by a relativistic electron beam

Experimental and theoretical investigations were made of the pumping of a copper vapour laser by a relativistic electron beam ($\bar\varepsilon\sim500$ keV, $I\sim3$ kA, $\tau\sim60$ ns). The results obtained (energy of laser pulses $\sim30$ mJ, efficiency $\sim1.5\%$ – $3\%$ at a neon pressure of $\sim0.02$ bar) were far from those expected. An analysis of the experimental and calculated data showed that the required concentration of the copper vapour in the atomic state was not reached in the active zone and that the process of pumping under these conditions was unconventional: the energy was transferred from the electron beam to the medium not by collisions with gas atoms (ionisation losses) but by the interaction of a beam-induced eddy electric field with the beam plasma.