Edward F. Gabl

On grid launched linear and nonlinear ion-acoustic waves

A series of experiments is described on grid excited linear and nonlinear ion acoustic waves. A multiple ion-acoustic shock formation is simulated. The excitation of solitons or a dispersing wave train can be used as a plasma diagnostic. Electrostatically coupled excitation of pseudowaves is observed.

Perturbing conductor effects on wave studies in a double plasma device

The effects on ion‐acoustic wave propagation caused by the introduction of a large biased metal plate close to and parallel to the separation grid in the target chamber of a double plasma machine are experimentally examined. It is found that the biased plate can re‐excite ion‐acoustic waves and can act as an externally controlled phase shifter.

On the oblique collision of unequal amplitude ion-acoustic solitons in a field-free plasma☆

Abstract Experiments on the oblique collision of unequal amplitude ion-acoustic solitons in a plasma are described. The experimental results are interpreted in terms of a resonance interaction theory derived from the Kadmotsev-Petviashvili equation.

On the evolution of an ion phase-space vortex

Conditions which allow the formation of a stable ion phase-space vortex in a double plasma machine are reported. A high frequency propagating signal with a frequency ~ fpi/2 which cannot be associated with a dispersing Airy function is observed on the trailing shoulder of the hole.

Characterization of sub-10-μm 30-ps flash duration point sources for X radiography

Flash x radiography can provide important information about high‐density, high‐opacity plasmas. Experiments at KMS investigated the characteristics of point x‐ray sources produced when coated fibers, wires, and mounted particles were irradiated with high intensity (I>1016 W/cm2) green laser light. The target materials Bi, CsI, Au, and Ag were evaluated in the areas of (1) the spatial and temporal resolutions that can be achieved, (2) the effect of source size and laser pulse duration on x‐ray signal strength, and (3) the practical considerations associated with using the technique to actually obtain radiographs of accelerated polyvinyl alcohol shells.

Ion-acoustic solitons in a multi component plasma: comparison of different theoretical models

Conditions for the existence of ion-acoustic solitons have been derived and studied for a warm multi-ion component plasma with two electron temperatures. The models: (a) reductive perturbation method (using KdV equation), (b) warm ion fluid theory based on a method by Sakanaka (1972) and (c) kinetic theory approach have been compared.

On grid launched linear and nonlinear ion-acoustic waves. III

For pt.II see ibid., vol.26, no.6, p.799 (1984). The authors extent their study on grid excited ion-acoustic solitons to examine far field radiation characteristics. In particular, for propagation distances greater than any launching grid dimension, the solitons propagate as spherically expanding shells.

Excitation of a two‐dimensional ion‐acoustic soliton

A flat, disk‐shaped ion‐acoustic soliton has been excited in a large collisionless plasma. The soliton appears to be stable, its amplitude is constant, and its broader width perpendicular to the direction of propagation slowly decreases as the soliton propagates.

On the resonant interaction of spherical ion-acoustic solitons

Abstract The resonant interaction of two spherical ion-acoustic solitons is observed. A new soliton whose amplitude is approximately three times the colliding solitons amplitude is created. The spatial growth and decay of the enhancement is noted.

Two‐dimensional evolution of an ion‐acoustic soliton

The two‐dimensional evolution of an ion‐acoustic soliton from a grid with regular or random perturbations in the direction transverse to the direction of the soliton propagation is experimentally examined. The soliton initially follows the contour of the exciting grid but evolves into a planar structure. These experimental results are compared with a model based on the higher dimensional Kadomtsev–Petviashvili equation. Both the theoretical and numerical predictions agree with the experiment.