Tapered-capillary pinch plasma as a candidate for bright EUV source

Summary form only given, as follows. In connection with the development of a bright EUV source, dynamics of pinching plasma in tapered capillary tubes is investigated. The basic configuration of the experimental setup is quite similar to conventional capillary source except the shape of the capillary wall. The capillary has thin conical wall, i.e., a Laval Nozzle geometry, and into which a working gas is supersonically injected. A high current discharge makes strong but slightly declining azimuthal magnetic field, which contracts the plasma radially and also axially. If the discharge condition influencing the plasma behavior is optimized, the plasma is expected to be compressed radially and also driven axially by the B-gradient made by the phased pinching. As the first step of the research and development, temporal behaviors of the plasma are observed using a fast streak camera. As has been predicted by numerical simulations, the pinching behaviors depend on the initial gas density, capillary length and the aspect ratio of the tubes. At a proper discharge condition, the framing photos confirm the point like formation and the pinching effect in radial and also axial direction. In the presentation, prospect for future study is discussed with the preliminary experimental results.