We consider the effective interaction between electrons due to the exchange
of virtual acoustic waves in a low temperature plasma. Electrons are supposed
to participate in rapid radial oscillations forming a spherically symmetric
plasma structure. We show that under certain conditions this effective
interaction can result in the attraction between oscillating electrons and can
be important for the dynamics of a plasmoid. Some possible applications of the
obtained results to the theory of natural long-lived plasma structures are also
discussed.Comment: 14 pages in LaTeX2e, two columns, 3 eps figures; minimal changes,
some typos are corrected; version published on-line in Proc. R. Soc.