Magnetic Rayleigh–Taylor instability mitigation in large-diameter gas puff Z-pinch implosions

• Published in: Physics of plasmas 2008-02, Vol.15 (2)
• Main Authors: Qi, N., Sze, H., Failor, B. H., Banister, J., Levine, J. S., Riordan, J. C., Steen, P., Sincerny, P., Lojewski, D.
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ARGON; COMPRESSION RATIO; FLUORESCENCE; IMPLOSIONS; LASERS; MASS DISTRIBUTION; PLASMA; PLASMA DENSITY; PLASMA DIAGNOSTICS; RADIATORS; RAYLEIGH-TAYLOR INSTABILITY; WAVE FORMS; X RADIATION; X-RAY SOURCES
• ISSN: 1070-664X; 1089-7674
• DOI: 10.1063/1.2839346

Recently, a new approach for efficiently generating K -shell x-rays in large-diameter, long-implosion time, structured argon gas Z-pinches has been demonstrated based on a “pusher-stabilizer-radiator” model. In this paper, direct observations of the Rayleigh–Taylor instability mitigation of a 12 - cm diameter, 200 - ns implosion time argon Z-pinch using a laser shearing interferometer (LSI) and a laser wavefront analyzer (LWA) are presented. Using a zero-dimensional snowplow model, the imploding plasma trajectories are calculated with the driver current waveforms and the initial mass distributions measured using the planar laser induced fluorescence method. From the LSI and LWA images, the plasma density and trajectory during the implosion are measured. The measured trajectory agrees with the snowplow calculations. The suppression of hydromagnetic instabilities in the “pusher-stabilizer-radiator” structured loads, leading to a high-compression ratio, high-yield Z-pinch, is discussed. For comparison, the LSI and LWA images of an alternative load (without stabilizer) show the evolution of a highly unstable Z-pinch.