The generalized covariant Virial Theorem can be used to provide both necessary conditions for plasmoid propagation equilibrium and accurate estimates of the disassembly time when such conditions are not met. Applied to long cylindrically symmetric geometries, it can be shown that radial confinement of the body of such a plasmoid requires continual transfer of momentum to the region external to the plasmoid; i.e., the plasmoid must have some external medium it can "lean" on. Such may be supplied by acceleration and loss of a sacrificial shell of material as proposed by A. Kadish and similarly by T. Lockner, or through coupling to an ambient ionized atmospheric component. This latter possibility has been explored and specific physical mechanisms identified and parameter ranges of validity established. The question of vacuum plasmoid propagation across a weak magnetic field has also been examined.
M L Sloan,
"Examination Of Aspects Of Plasmoid Propagation", Proc. SPIE 0873, Microwave and Particle Beam Sources and Propagation, (9 May 1988); doi: 10.1117/12.965107; https://doi.org/10.1117/12.965107