Experiments on the transient or ion-matrix sheath from 90 degrees convex and concave corners and randomly perturbed objects have been performed. Equiphase contours of ion acoustic waves launched from metallic structures yield results that are in substantial agreement with a numerical simulation and, for the case of the corners, with recent numerical investigations. Differences can be attributed, in part, to inhomogeneities found in the experimental plasma.

A technique to easily and quickly obtain, display, and analyze the transistor characteristics of pnp and npn bipolar junction transistors with a Macintosh personal computer is reported. Both the necessary hardware and software are described.

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Experiments demonstrate that it is possible to determine the characteristics of a plasma flowing past an object by locally modulating the plasma and measuring the resulting equiphase contours of the perturbation downstream. The technique is employed in studies of the wake region behind the object.