Plasma dynamics in capillary discharge soft x-ray lasers

The dynamics and stability of collapsing gas columns, generated by a fast capillary discharge setup, are studied for obtaining soft x-ray amplification in highly ionized ions. Electron temperature and density measurements at the peak of the compression stage are used for tuning the discharge parameters. Once the needed conditions were achieved, strong amplification of the 3s-3p transition in Ne-like Ar ions at 469 Å is observed. A gain coefficient of >0.75cm⁻¹ and a beam divergence of <5 mrad are measured along plasma columns of < 150 µm diameter and up to 165 mm length.