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.

No abstract

No abstract

A method of measuring the mean velocity of a flowing plasma is described. In this method ``blobs'' of plasma are extracted from the body of the flow by an electrostatic gating technique. Then the time of flight of the ``blob'' for a given distance is measured. Measurements of plasma velocities of 2×105 cm/sec have been made at total particle densities of 1012/cm3.