Experimental Analogue Study of Containment of Dense Plasmas in Resonant-Cavity Fields†

An analogue experiment has been devised to study the conditions for the equilibrium of dense plasma cores contained by r.f. cavity fields. Plasma cores are simulated by copper spheres, spheroids and other configurations. Frequency shifts that result from finite perturbations in (1) size, (2) position and (3) configuration are measured. The measurements are interpreted by use of the Wien-Ehrenfest adiabatic theorem to yield information on equilibrium of the core. Measurements indicate that cores in a spherical cavity are in stable equilibrium against all three types of perturbation only in the magnetic quadrupole mode and in higher order magnetic multipole modes of the cavity fields.