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Time dependence of (a) vapor density and (b) pressure, including the ablation pressure, for stainless steel treated by a 103 J=cm 2 GESA II generated electron beam.
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The process of electron beam interaction with metal targets was characterized using electrical and optical diagnostics. Electron beams with current density of 5–10 A∕cm2, electron energy up to 120 keV, pulse duration up to 200 μs, and cross-sectional area of 8–30 cm2 at the target surface were generated by GESA I and GESA II facilities. Streak imag...
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Context 1
... evaporated layer reaches a thickness of $5 lm, which corresponds to a total amount of evaporated atoms of $4 Â 10 19 cm À2 . The vapor temperature in the vicinity of the target surface is found to be 67% of the target surface temperature. Results for the vapor density and pressure in the Knudsen layer adjacent to the sample surface are shown in Fig. 7. The density of neutrals reaches $1.3 Â 10 19 cm À3 at the time of maximum surface tempera- ture. These neutrals leave the surface with a velocity of $0.9 Â 10 5 cm=s, which results in a substantial ablation pressure directed toward the surface. As seen in Fig. 7, this ablation pressure reaches values up to $8 Â 10 5 ...
Context 2
... and pressure in the Knudsen layer adjacent to the sample surface are shown in Fig. 7. The density of neutrals reaches $1.3 Â 10 19 cm À3 at the time of maximum surface tempera- ture. These neutrals leave the surface with a velocity of $0.9 Â 10 5 cm=s, which results in a substantial ablation pressure directed toward the surface. As seen in Fig. 7, this ablation pressure reaches values up to $8 Â 10 5 ...
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has been studied experimentally and computationally. The relatively low
voltage and high current required for materials surface modification
applications leads to complicated beam dynamics as the Alfven limit is
approached. Transport and focusing of the high ν/γ beam was
done in a sub-Torr, neutral gas-filled, conducting tube in the
ion-focused regime. In this regime, beam space charge forces are
progressively neutralized to allow focusing of the beam by its
self-magnetic field. The beam exhibits stable envelope oscillations as
it is efficiently and reproducibly propagated for distances greater than
a betatron wavelength. Experimental results follow the trends seen in
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half-current radius decreased by a factor of 2.84. This results in an
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