Pre-pulse current measurement of the fast high-current capillary-discharge experiment

We have built two experimental apparatuses CAPEX and CAPEX-U as XUV sources, which are based on the fast capillary discharge. On both these devices we have observed lasing at 46.9 nm (Ne-like Ar line). However, these devices are not only lasing at 46.9 nm, but they are used for testing a possibility of amplification at the wavelength below 20 nm that have more practical applications. Nowadays, the fast high-current capillary discharge experiments with nitrogen-filled capillary are in progress as well. In this paper the pre-pulse capillary current and its influence on discharge parameters (the main current amplitude and duration, the plasma temperature and ionization stage) will be studied with the help of spectroscopic measurements.