The dispersion relation is calculated for the interchange instabilities due to the resonance between the drift wave and the grad B drift motion of ions. Either a low plasma density or nonisotropic temperature may lead to instability.
The electron density of transient plasma was measured with Michelson type CO2 laser interferometer. The stability of the CO2 laser, the directivity of the laser beam and the accuracy of the density measurement were investigated.
Gases (CO Xe and H) are freezed into a column, 0.4mm in diameter and about 0.7mm long, which is moved in a vacuum chamber by a pipe and remains hanging down. The column is thined at the root as a result of gradual evaporation and is cut by a low power laser pulse or by a edge driven mechanically. The light signal scattered from the falling column triggers a Q-switched laser (100 MW). The laser light pulse is focused on a particle isolated at the center of a vacuum chamber to produce high-temperature and high-density plasma. Such plasma will contribute to the fundamental research of plasma physics.