Z-Pinch-Generated X Rays Demonstrate Potential for Indirect-Drive ICF Experiments

Abstract

Hohlraums measuring 6 mm in diameter by 7 mm in height have been heated by x rays from a Z pinch. Over the measured x-ray input powers P of 0.7 to 13 TW, the hohlraum radiation temperature T increases from ϳ55 to ϳ130 eV, and is in agreement with the Planckian relation T ϳ P 1͞4 . The results suggest that indirect-drive inertial-confinement-fusion experiments involving National Ignition Facility relevant pulse shapes and ,2 mm diameter capsules can be studied using this arrangement.

Dynamics of a Z-pinch x-ray source for heating inertial-confinement-fusion relevant hohlraums to 120–160 eV

“…The increase in temperature measured with the red;ced-scale relative to the NE-scale hohlraum, from these zpinch generated x-rays, is consistent with that expected from the Planckian relation. The result complements that which showed the temperature of the NIF-scale hohlraum as a function of x-ray power from a z-pinch to be also consistent with the Planckian relation [29].…”

“…The measurements are also consistent with the absolute value of the expected temperature (solid curve in Fig. 17) calculated from a radiosity code [31] that uses the measured average incident power of 13 TW and wall albedo of 0.8 (estimated for these conditions [29]). Figure 18 plots the measured peak temperature of the reduced-scale hohlraurn as a function of the density of the foam filling its interior.…”

“…14 and 15 is liily a manifestation of such processes. Earlier experiments support this conjecture [29]. In these experiments, images from fast-framing pinhole cameras viewing the exit of the diagnostic normal to the axis of the hole show plasma exiting the hole consistent with these time scales.…”

“…To date, the large-volume z-pinch driven hohlraum has developed a temperature of 95*5 eV in a 17-mm diameter by 15-mm high hohlraum, when heated by radiation generated external to a single pinch [28], The energy-efficient dynamic hohlraum, which uses radiation generated internal to a radially converging target heated by the imploding wire array, has developed temperatures ranging from 80 to 180 eV as the diameter of a 10-mm high hohlraum compresses from 5 to 1.6 mm [22]. And the static-wall hohlraum, which combines features from both concepts, has developed a temperature of 130+7 eV in a NIF-scale hohlraurn (6-mm diameter by 7-mm high) [29], again when heated by xrays from a single pinch.…”

Overview of the dynamic-hohlraum x-ray source at Sandia National Laboratories.

“…Dynamic-hohlraums (DHs) [1][2][3][4] driven by a wire-array z-pinch are being developed and used as intense blackbody x-ray sources for inertialconfinement-fusion (ICF) [5][6][7][8][9] and hightemperature radiation-flow experiments [10][11] (Fig. 1).…”