High energy density physics and high resolution point-projection imaging with X pinch plasmas

Summary form only given. X pinch plasmas are produced by exploding two metal wires that cross and touch at a single point (in the form of an X) using a 200-400 kA, 100 ns (FWHM) current pulse. A magnetically driven implosion near the original cross point of the wires leads to the emission of one or more <1 ns intense X-ray bursts. X pinches have successfully been developed as a high space- and time-resolution radiographic diagnostic in the 1.5-8 keV range. Individual X-ray bursts with energy >2.5 keV are emitted; the duration of these bursts can be <100 ps. These small, transient X-ray sources are also physically interesting plasmas because additional measurements imply that their energy density may be >10/sup 28/eV/cm/sup 3/ at the moment of the X-ray burst. Furthermore, their volume power density is >10/sup 21/ W/cm/sup 3/ with a surface flux of >10/sup 16/ W/cm/sup 2/. Radiographs of the X pinch implosion process show that a z-pinch forms in the region of the original wire cross point about 2 ns before the characteristic X-ray bursts occur. The z-pinch implodes and gaps develop in the radiographic images coincident in time and space with the X-ray burst(s). Immediately following the moment of X-ray burst emission, explosive disassembly of the z-pinch occurs on a 1 ns time scale, accompanied by the launching of shockwaves into the surrounding material. Time-integrated spectroscopic measurements of X pinch radiation indicate electron temperatures of 500-1300 eV, depending of the wire material, and in some cases densities in excess of 10/sup 22//cm/sup 3/. Time-resolved spectroscopic measurements using an X-ray streak camera are presently underway that may reveal the physical mechanisms which lead to the generation of the X-ray bursts.