Time-Dependent Helical Magnetic Field Effects on Cylindrical Liner Ablations**

During cylindrical liner implosions and ablations, magneto Rayleigh-Taylor (MRT) and general magnetohydrodynamic (MHD) instabilities (such as the m=0 “sausage” and the m=1 “kink” instabilities) form.  Simulations have indicated that adding a time dependent helical magnetic field using a dynamic screw pinch suppresses MRT instability growth¹.  We have modeled and fabricated several helical return current structures to generate such a field configuration, with a predicted axial magnetic field of 10 T for peak currents of 550 kA. Simulations of the expected magnetic field profile will be presented, as well as experimental measurements of the magnetic field values achieved, and a comparison of the instabilities observed.

 

1. P.F. Schmit, et al., (2016). Controlling Rayleigh-Taylor Instabilities in Magnetically Driven Solid Metal Shells by Means of a Dynamic Screw Pinch. Phys. Rev. Lett., 117, 205001.