Magnetoelectric confinement and stabilization of the plasma column in a soft-x-ray Ar(+8) laser, which is excited by a capillary Z pinch, via the combined magnetic and electric fields of the gliding surface discharge is experimentally demonstrated. Unlike soft-x-ray lasers excited by the conventional capillary Z pinches, the magnetoelectric confinement and stabilization of plasma do provide the laser operation without using any external preionization circuit.

The most accurate models of the capillary Z-pinches used for excitation of soft X-ray lasers and photolithography XUV sources currently are based on the magnetohydrodynamics theory (MHD). The output of MHD-based models greatly depends on details in the mathematical description, such as initial and boundary conditions, approximations of plasma parameters, etc. Small experimental groups who develop soft X-ray/XUV sources often use the simplest Z-pinch models for analysis of their experimental results, despite of these models are inconsistent with the MHD equations. In the present study, keeping only the essential terms in the MHD equations, we obtained a simplified MHD model of cylindrically symmetric capillary Z-pinch. The model gives accurate results compared to experiments with argon plasmas, and provides simple analysis of temporal evolution of main plasma parameters. The results clarify the influence of viscosity, heat flux and approximations of plasma conductivity on the dynamics of capillary Z-pinch plasmas. The model can be useful for researchers, especially experimentalists, who develop the soft X-ray/XUV sources.

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The present study is focused on the demonstration of the most critical parameters of the pumping scheme of a table-top Ar +8 -laser excited by discharges with relatively low current and voltage (I ≤ 20 kA, U ≤ 200 kV) in long (L ∼ 0.5 m) capillaries. The most critical parameters of the pumping scheme were analyzed and then adjusted experimentally. The table-top size is attributed to the use of a low-inductance co-axial discharge configuration that decreases the voltage and current necessary for laser excitation. Low inductance is achieved by using a capillary, water-capacitor and water spark-gap placed into a chamber filled with deionized water. The capillary z-pinch is produced by the water capacitor, which is pulse-charged by a six-stage Marx generator, optimized for the low-inductance discharge configuration. Optimization is performed by adjusting the value of the charging inductance and the peak charging voltage with a water spark-gap. At the optimal conditions laser pulses with a Gaussian-like intensity distribution and divergence angle ∼ 1 mrad and energy ∼ 10 μJ are generated. The physical method for generation of a laser beam with such parameters is based on the use of a long (L = 0.45 m) capillary plasma.