Magnetically driven implosions are susceptible to magnetohydrodynamic instabilities, including the magneto-Rayleigh-Taylor instability (MRTI). To reduce MRTI growth in solid-metal liner implo-sions, the use of a dynamic screw pinch (DSP) has been proposed [P. F. Schmit et al., Phys. Rev. Lett. 117, 205001 (2016)]. In a DSP con guration, a helical return-current structure surrounds the liner, resulting in a helical magnetic eld that drives the implosion. Here, we present the rst experimental tests of a solid-metal liner implosion driven by a DSP. Using the 1-MA, 100{200-ns COBRA pulsed-power driver, we tested three DSP cases (with peak axial magnetic elds of 2 T, 14 T, and 20 T) and a standard z-pinch (SZP) case (with a straight return-current structure and thus zero axial eld). The liners had an initial radius of 3.2 mm and were made from 650-nm-thick aluminum foil. Images collected during the experiments reveal that helical MRTI modes developed in the DSP cases, while non-helical (azimuthally symmetric) MRTI modes developed in the SZP case. Additionally, the MRTI amplitudes for the 14-T and 20-T DSP cases were smaller than in the SZP case. Speci cally, when the liner had imploded to half of its initial radius, the MRTI amplitudes for the SZP case and for the 14-T and 20-T DSP cases were, respectively, 1.1-0.3 mm, 0.7-0.2 mm, and 0.3-0.1 mm. Relative to the SZP, the stabilization obtained using the DSP agrees reasonably well with theoretical estimates.
Campbell, Paul C., et al. "Stabilization of Liner Implosions via a Dynamic Screw Pinch." Physical Review Letters, vol. 125, no. 3, Jul. 2020. https://doi.org/10.1103/PhysRevLett.125.035001
Campbell, Paul C., Jones, T. M., Woolstrum, J. M., Jordan, N. M., Schmit, P. F., Greenly, J. B., Potter, W. M., Lavine, E. S., Kusse, B. R., Hammer, D. A., & McBride, R. D. (2020). Stabilization of Liner Implosions via a Dynamic Screw Pinch. Physical Review Letters, 125(3). https://doi.org/10.1103/PhysRevLett.125.035001
Campbell, Paul C., Jones, T. M., Woolstrum, J. M., et al., "Stabilization of Liner Implosions via a Dynamic Screw Pinch," Physical Review Letters 125, no. 3 (2020), https://doi.org/10.1103/PhysRevLett.125.035001
@article{osti_1634186,
author = {Campbell, Paul C. and Jones, T. M. and Woolstrum, J. M. and Jordan, N. M. and Schmit, P. F. and Greenly, J. B. and Potter, W. M. and Lavine, E. S. and Kusse, B. R. and Hammer, D. A. and others},
title = {Stabilization of Liner Implosions via a Dynamic Screw Pinch},
annote = {Magnetically driven implosions are susceptible to magnetohydrodynamic instabilities, including the magneto-Rayleigh-Taylor instability (MRTI). To reduce MRTI growth in solid-metal liner implo-sions, the use of a dynamic screw pinch (DSP) has been proposed [P. F. Schmit et al., Phys. Rev. Lett. 117, 205001 (2016)]. In a DSP con guration, a helical return-current structure surrounds the liner, resulting in a helical magnetic eld that drives the implosion. Here, we present the rst experimental tests of a solid-metal liner implosion driven by a DSP. Using the 1-MA, 100{200-ns COBRA pulsed-power driver, we tested three DSP cases (with peak axial magnetic elds of 2 T, 14 T, and 20 T) and a standard z-pinch (SZP) case (with a straight return-current structure and thus zero axial eld). The liners had an initial radius of 3.2 mm and were made from 650-nm-thick aluminum foil. Images collected during the experiments reveal that helical MRTI modes developed in the DSP cases, while non-helical (azimuthally symmetric) MRTI modes developed in the SZP case. Additionally, the MRTI amplitudes for the 14-T and 20-T DSP cases were smaller than in the SZP case. Speci cally, when the liner had imploded to half of its initial radius, the MRTI amplitudes for the SZP case and for the 14-T and 20-T DSP cases were, respectively, 1.1-0.3 mm, 0.7-0.2 mm, and 0.3-0.1 mm. Relative to the SZP, the stabilization obtained using the DSP agrees reasonably well with theoretical estimates.},
doi = {10.1103/PhysRevLett.125.035001},
url = {https://www.osti.gov/biblio/1634186},
journal = {Physical Review Letters},
issn = {ISSN PRLTAO},
number = {3},
volume = {125},
place = {United States},
publisher = {American Physical Society (APS)},
year = {2020},
month = {07}}