David W. Aossey

Soliton propagation, collision, and reflection at a sheath in a positive ion–negative ion plasma

Experiments on the propagation and collision of a Korteweg–deVries soliton in a positive ion–negative ion plasma are described. Both a one‐dimensional overtaking collision and a two‐dimensional resonant collision are examined. Soliton propagation into a steady‐state plasma sheath created by an additional biased metal plate in such a plasma is large enough that the detailed soliton motion in the locally inhomogeneous plasma can be easily studied. A partial reflection and partial transmission of the soliton at a critical density within the sheath is observed and interpreted.

Sheath evolution in a negative ion plasma

The spatial and temporal evolution of a sheath surrounding a planar electrode whose potential is suddenly decreased in a quasineutral plasma consisting of positive ions, negative ions, and electrons is numerically investigated. The model predicts several features observed in recent laboratory experiments directed toward the excitation and subsequent propagation of solitons in such a plasma.

Interacting geometric solitons in a positive ion-negative ion plasma

Density perturbations launched from a planar-hemispherical exciter surface are investigated and shown to support the existence and interaction of planar and spherical KdV solitons. Equitime contours obtained in the propagation region introduce evidence of edge launched cylindrical solitons. Confirmation of a resonant condition between cylindrical solitons launched from the edges of a V-shaped exciter is presented. Features of the sheath enclosed within the V-shaped exciter for a positive ion-negative ion plasma are compared with a similar sheath in a normal electron-ion plasma.

Variations of plasma parameters in unmagnetized and magnetized argon-SF6-electron plasmas

Variations in plasma parameters in both unmagnetized and magnetized plasma environments are reported for argon-SF6-electron plasmas with increasing negative ion concentrations epsilon . Characteristic changes in electron temperature, plasma potential and electron saturation current in the region of the experimental magnets with changing epsilon are described and interpreted. Particle density reductions near the magnetic surface are reported. Two-dimensional density profiles of the region adjacent to the experimental magnets are presented for various values of epsilon .

A Heuristic Approach to Soliton-Soliton Resonant Interaction

An intuitive model that describes the resonant interaction of solitons that are defined by the Kadomtsev-Petviashvili equation is presented. The model is based on a geometrical interpretation of the interaction and some fundamental properties of solitons.