Weak radial expansion of a Z-pinch plasma column during its strong initial ohmic heating phase is expected when the generation of a confining magnetic field is assisted by a correctly formed electron beam pulse. Appropriate one-dimensional magnetohydrodynamic equations are numerically solved, and the observed increase of plasma radius as a function of time for various discharge parameters is compared to a normal Z-pinch discharge initiation.
Heikkinen, J., & Karttunen, S. (1989). Reduction of thermal expansion in Z-pinches by electron beam assisted magnetic field generation. Plasma Physics and Controlled Fusion, 31(7), 1035-1048. https://doi.org/10.1088/0741-3335/31/7/003