Laboratory Study of the Wakes of Small Cylinders under Ionospheric Satellite Conditions

Abstract

The wakes of cylinders small compared with the Debye length have been studied in a collision-free plasma wind tunnel where the flow around ionospheric satellites can be simulated. No magnetic field was applied in these experiments. A small cylinder was found to excite in its path a disturbance consisting of a decaying oscillation on the centerline at the ion plasma frequency and a series of “waves” which originate at the centerline oscillation. The wake angle was dependent on the body potential and on the ratio of body radius to Debye length, and took on values well above and well below the Mach angle based on the ion wave speed. At large negative body potentials, the first “wave” emanating from the body was identified as a group of ions which had been deflected by the electric field of the cylinder.