Sc-Si multilayers are suggested as high-reflectivity coatings for a VUV interval of 35-50 nm. Fabricated mirrors show normal-incidence reflectivity of 30-54%, which is high enough for effective manipulation of the beams of compact-discharge, laser-driven x-ray lasers. The values obtained are not, however, limits for Sc-Si coatings. Theoretical estimations as well as electron microscopy studies of Sc-Si interfaces indicate a large potential for a further increase in their reflectivity.

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The electron energy distribution function measured at the channel exit of a small Hall-type thruster is interpreted as a beam–plasma electron distribution function with electron beam energy of several tens of electronvolts. Though unstable, the distribution function does not correspond to the completely quasilinear relaxed beam function. Comparison with the measured function in the vicinity of the channel exit shows that the electron beam energy is about 30 eV for the total voltage applied ∼200 V. The contribution of the electron beam is shown to be essential in the ionization of the working gas, even when only the single ionization processes are considered.

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