Azimuthal clumping instabilities in a z-pinch wire array

Abstract

Summary form only given. Recent simulations of an idealized, high wire-number array Z-pinch reveal a strong azimuthal clumping instability. This instability is due to the mutual attraction of neighboring wires that carry current in the same direction. The unstable modes are heavily crowded, the most unstable mode being the pi-mode, where the neighboring wires pair together. The temporal evolution of this most unstable azimuthal mode can be analyzed, exclusively, by simulating just one wire in an N-wire array, adopting reflection boundary conditions on an angular sector that contains that single wire. Thus, codes such as ALEGRA, which can invoke this reflection boundary condition, automatically filter all other azimuthal modes except the pi-mode and can be used to study the instability with and without the inclusion of a coronal plasma. This simulation capability allows for a convenient study of the coupling of this most unstable azimuthal clumping instability with the radial and axial magnetic Rayleigh-Taylor instability. Simulation results will be used to quantify the magnitude of the instability as a function of wire number scaling by simply changing the sector angle used