Plasmas composed of injected electron-hole pairs in $p$-type indium antimonide have been studied: The injection times have been measured. Pinching of the plasma has been observed. The current-voltage curves show a steep rise at voltages well below those required for breakdown, indicating a large increase in carrier density before breakdown. The Hall voltage measured as a function of current changed sign from that expected for hole transport to that expected for electron transport. Negative resistances have been observed in the plasma in the presence of transverse magnetic fields. Longitudinal magnetic fields decreased the plasma density, probably because of an increased radial diffusion of the plasma to the surface. Coherent oscillations have been observed on top of the pinch both with and without longitudinal fields. Their dependence on current and magnetic field is described.

• Received 2 August 1961

DOI:https://doi.org/10.1103/PhysRev.124.1745