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Description
Soft x-ray radiography (≈ 1÷2 keV) of a bismuth and aluminum metal-puff plasma formed by the high-current vacuum arc discharge is presented. The plasma gun with the arc current ≈ 60 kA and the current rise time ≈ 7 μs was used to produce a metal-puff plasma jets. The compact pulsed radiograph XPG-1 (250 kA, 220 ns) with X-pinch and PZ-pinch load was used as a source of the soft X-ray radiation. X-pinch load consisted of four Mo wires with diameter 25 µm. PZ-pinch load is a miniature plasma jet. Jet length is equal to 1.5 mm. The spatial and temporal parameters of the radiating hot spot of X-pinch and PZ-pinch loads are close to each other. X-ray backlighting images of the researched plasma jet and the Bi step-wedge with a step thickness of ≈ 100 nm were recorded simultaneously at the experiment. The comparison of the plasma jet x-ray image has enabled to estimate the dependencies of the jet linear mass on the arc current. Experiments have shown that when the arc current density reaches ≈ 3•105 A/cm2 the evaporation rate of the electrode material reaches ≈ 100 µg/µs, that under the plasma velocity ≈ 0.5 cm/µs provides a plasma jet linear mass ≈ 200 µg/cm. At a distance of ≈ 1-2 mm from the arc cathode surface the sharp increase of jet linear mass (up to ≈ 500 µg/cm) was occurred.
Work supported by the grant Russian Scientific Foundation # 16-19-10142.
