Shape stability for a plasma contained within a standing electromagnetic field

For an over-dense plasma located within a resonant cavity and surrounded by standing electromagnetic radiation, it is shown that shape stability depends only on the ratio of the mean plasma radius (ra) to the wavelength of the surrounding radiation. For an initial cavity mode wavenumber k10, stability occurs for k10 ra≲π. Becausetheplasma-surfaceoscillation frequency νλ is shown to scale linearly with λ (the order of the surface wave), νλ remains small compared with the electromagnetic field frequency for stable plasmas. These results are of significance in designing inertial fusion experiments in which intense electromagnetic fields are used for heating and compressing a dense plasma.