Gas Jet Plasma Research Articles

Plasma Channel Formation and Guiding during High Intensity Short Pulse Laser Plasma Experiments

A plasma channel is formed behind a self-guided, subpicosecond, 2 TW laser pulse in a hydrogen gas jet plasma. The channel is produced from the radial expulsion of plasma ions due to charge separation created in the displacement (or cavitation) of plasma electrons by the large ponderomotive force of the laser. Using Thomson scattering diagnostics and mode structure measurements, an intense trailing laser pulse $(I\ensuremath{\sim}5\ifmmode\times\else\texttimes\fi{}{10}^{16}\mathrm{W}/{\mathrm{cm}}^{2})$ is observed to be guided throughout the length of this channel for about 20 Rayleigh lengths, approximately equal to the propagation length of the self-guided pump laser pulse.

Measurement of the local electron density by means of stimulated Raman scattering in a laser-produced gas jet plasma

By measuring the spectrum of the backscattered light from a short-pulse laser-produced plasma in a gas jet, a direct and highly accurate measurement of the local electron density can be obtained. The measurement is based on the density-dependent spectral shift of the backscattered Raman wave.

A plasma jet operated by sublimation gases.

Evaluation of performance has been made empirically for an original type of plasma jet which is operated by using sublimation gases of solids. Both the production and the heating of the sublimation gases are conducted at the same time by arc discharges ; hence the working gases can be generated on demand. The extinctions and ignitions are repeatedly possible and instantaneous with the application or interruption of arc discharges when appropriate solids are employed as its charge, and the sublimation rate of the charge can be controlled by the arc intensity. measurements show that the efficiency of this plasma jet is in no way inferior to the ordinary gas plasma jet, and can be still improved by employing a composit type of charge solid or a consumption type of electrode in order that the evaporation gases may react and release high combustion energy.

プラズマジェットの衝突力の測定 平行平板構造のロードセルを用いた試作装置による測定

The new measuring apparatus of plasma jet force using the load-cell on the parallel beams structure has been developed and applied to the measurement of argon gas plasma jet force.The load-cell of parallel beams structure is easily manufactured and has excellent sensitivity of measurement. The experimental results of the plasma jet force measurement are described and discussed.It has been indicated that the plasma jet force depends on arc current, arc voltage, working gas flow rate, gas supplying method, and stand-off condition. The plasma jet force is closely related with the input power and is proportion to the square root of input power.

X-ray lithography using a pulsed plasma source

An imploding gas jet plasma has been developed as a soft x-ray source for lithographic applications. The plasma is an efficient source of krypton L radiation, which closely matches the wavelength of tungsten anode electron bombardment sources. Resist exposures have been made to evaluate the suitability of the source and determine the filtering requirements necessary to protect the resist. COP resist required 20 shots for a proper exposure; no reciprocity failure was observed with these pulsed, high-power exposures.