Observation of emission process in hydrogen-like nitrogen Z-pinch discharge with time integrated soft X-ray spectrum pinhole image

Abstract

The emission spectra of hydrogen-like nitrogen Balmer at the wavelength of 13.4 nm in capillary Z-pinch discharge plasma are experimentally examined. Ionization to fully strip nitrogen at the pinch maximum, and subsequent rapid expansion cooling are required to establish the population inversion between the principal quantum number of n ¼ 2 and n ¼ 3. The ionization and recombination processes with estimated plasma parameters are evaluated by utilizing a time integrated spectrum pinhole image containing radial spatial information. A cylindrical capillary plasma is pinched by a triangular pulsed current with peak amplitude of 50 kA and pulse width of 50 ns. V C 2013 American Institute of Physics. [http://dx.

Time-resolved EUV spectra from nitrogen Z-pinching capillary discharge

“…In later calculations gain has been predicted also for 5 mm diameter capillary with similar current and lower initial nitrogen pressure 8 . Several experiments [9][10][11][12] have been done to prove those predictions, but no ASE has been measured. In 9,10 conditions for lasing were nearly reached, except of the electron temperature in the pinch, which was around 70% of the required value.…”

Discharge driver for 13.4 nm XUV laser

“…Numerical simulations also predict high gain in H-like Nitrogen 1 with a discharge current I > 60 kA and a current slope dI/dt ~ 2×10 12 As -1 , which are obtainable using a capillary discharge driver with an endurable charging voltage of V ~ 100s kV. Several research groups attempt to obtain laser output with drivers with parameters approaching theoretical requirements [13][14][15][16] . No amplification had been observed yet, but plasma diagnostic indicates, that plasma parameters are very close to the one, for which theory predicts gain 13 , but there is need for increasing discharge current amplitude.…”

“…No amplification had been observed yet, but plasma diagnostic indicates, that plasma parameters are very close to the one, for which theory predicts gain 13 , but there is need for increasing discharge current amplitude. Driver's basic parameters used in experiments from [13][14][15][16] are summarized in Table 1. In Table 1, there are also parameters of the new driver expected from PSpice simulations.…”

Effect of the rate of rise in discharge current on the output of a 46.9-nm soft X-ray laser based on capillary discharge

“…It is worth mentioning here that directed EUV emission has also been reported from discharge plasma at shorter wavelengths ranging from 12 to 16 nm [23]. Efforts are presently going on in this direction in various laboratories worldwide to demonstrate X-ray lasing at a wavelength of 13.4 nm in nitrogen z-pinch plasma using a capillary discharge system [24][25][26][27]. Unlike the 46.9-nm X-ray laser, this is based on recombination pumping scheme which requires fast heating of the plasma followed by fast cooling of the hot plasma.…”