Sheath broadening in imploding z-pinches due to large-bandwidth Rayleigh-Taylor instability

The magnetic Rayleigh-Taylor (RT) instability has been predicted¹ and observed² to cause break-up of the plasma sheath in imploding z-pinches. In this work we show that, for the type of density profile encountered in strongly-radiating pinches, instability at very short wavelengths grows to the non-linear stage and seeds progressively longer wavelengths. The result is a self-similar broadening of the sheath as found for mix layers in fluid RT unstable systems³.