Shadow Imaging Study of Z-Pinch Dynamic Hohlraum

Authors: Chen Faxin, Feng Jinghua, Yang Jianlun, Li Linbo, Zhou Lin

Abstract:

In order to obtaining the dynamic evolution image of Tungsten array for foam padding, and to research the form of interaction between Tungsten plasma and foam column, a shadow imaging system of four-frame ultraviolet probe laser (266nm)has been designed on 1MA pulse power device. The time resolution of the system is 2.5ns, and static space resolution is superior to 70μm. The radial shadowgraphy image reveals the whole process from the melting and expansion of solid wire to the interaction of the precursor plasma and the foam, from the pinch to rebound inflation. The image shows the continuous interaction of Tungsten plasma and foam in a form of “Raining" within a time of about 50ns, the plasma shell structure has not been found in the whole period of pinch. The quantitative analysis indicates the minimum pinching speed of the foam column is 1.0×106cm/s, and maximum pinching speed is 6.0×106cm/s, and the axial stagnation diameter is approx 1mm.

Keywords: Dynamic hohlraum, Shadowgraphy image, Foam evolution.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1081563

References:

[1] J. P. Apruzese, R. W. Clark, P. C. Kepple, and J. Davis. "Diagnosing dynamic hohlraums with tracer absorption line spectroscopy," Phys. Plasmas, vol. 12, pp. 0127051-012708, Jan 2005.
[2] T. W. L. Sanford, R. W. Lemke, R. C. Mock, G. A. Chandler et al. "Dynamics and characteristics of a 215eV dynamic-hohlraum x-ray source on Z," Phys. Plasmas, vol. 9, pp. 3573-3594, Aug 2002.
[3] T. W. L. Sanford, T. J. Nash, and R. C. Mock, et al. "Evidence and mechanisms of axial-radiation asymmetry in dynamic hohlraums driven by wire-array Z pinches," Phys. Plasmas, vol. 12, pp. 0227011-02270114, Jan 2005.
[4] T. W. L. Sanford, T. J. Nash, and R. C. Mock, et al. "Diagnosed internal temperatures and shock evolution provide insight on dynamic-Hohlraum-s axial radiation production and asymmetry," Phys. Plasmas, vol. 13, pp. 0127011-01270121, Jan 2006.