Titanium K-Shell X-Ray Production from High Velocity Wire Arrays Implosions on the 20-MA Z Accelerator

The advent of the 20-MA Z accelerator [R.B. Spielman, C. Deeney, G.A. Chandler, et al., Phys. Plasmas 5, 2105, (1997)] has enabled implosions of large diameter, high-wire-number arrays of titanium to begin testing Z-pinch K-shell scaling theories. The 2-cm long titanium arrays, which were mounted on a 40-mm diameter, produced between 75{+-}15 to 125{+-}20 kJ of K-shell x-rays. Mass scans indicate that, as predicted, higher velocity implosions in the series produced higher x-ray yields. Spectroscopic analyses indicate that these high velocity implosions achieved peak electron temperatures from 2.7{+-}0.1 to 3.2{+-}0.2 keV and obtained a K-shell emission mass participation of up to 12%

Experimental Studies of Magnetically Driven Plasma Jets

We present experimental results on the formation of supersonic, radiatively cooled jets driven by pressure due to the toroidal magnetic field generated by the 1.5 MA, 250 ns current from the MAGPIE generator. The morphology of the jet produced in the experiments is relevant to astrophysical jet scenarios in which a jet on the axis of a magnetic cavity is collimated by a toroidal magnetic field as it expands into the ambient medium. The jets in the experiments have similar Mach number, plasma beta and cooling parameter to those in protostellar jets. Additionally the Reynolds, magnetic Reynolds and Peclet numbers are much larger than unity, allowing the experiments to be scaled to astrophysical flows. The experimental configuration allows for the generation of episodic magnetic cavities, suggesting that periodic fluctuations near the source may be responsible for some of the variability observed in astrophysical jets. Preliminary measurements of kinetic, magnetic and Poynting energy of the jets in our experiments are presented and discussed, together with estimates of their temperature and trapped toroidal magnetic field.Comment: 7 pages, 6 figures, accepted for publication in Astrophysics & Space Scienc

Z-SCALING OF GAIN IN PLASMA X-RAY LASER

L'amplification substantielle de rayons X a été récemment démontrée sur la raie 3-2 du C5+ et sur des raies 3p-3s du Se24+ et de Y29+. Nous considérons comment obtenir une amplification sur les mêmes transitions à plus courte longueur d'onde, en utilisant des éléments à numéro atomique plus élevé. Nous trouvons que l'addition d'autres éléments dans le plasma pour augmenter le refroidissement radiatif est très utile pour accélérer la recombinaison et l'amplification de transition 3-2 hydrogénoides. Nous présentons aussi une comparaison des caractéristiques atomiques et des conditions d'inversion pour les ions hydrogénoides et néonoides.Substantial amplification of x-rays has been recently demonstrated on the 3-2 line of C5+ and on some 3p-3s transitions of Se24+ and Y29+. We consider methods of obtaining amplification on these same transitions at shorter wavelength, by using elements of higher atomic number. We find that the addition of other elements to the plasma to enhance radiative cooling is very useful for accelerating the recombination and amplification of the hydrogenic 3-2 line. We also present a comparison of the atomic properties and conditions required for inversion for hydrogenic and neonlike ions