Experiments designed to measure the interaction of an intense rotating relativistic electron beam with a plasma have been carried out. Detailed agreement with the measured and calculated magnetic field perturbations at a density of 1014 cm−3 is found. To obtain agreement between the calculated and measured probe responses when the plasma density is varied, it is necessary to assume a non-classical conductivity that is proportional to the plasma density. At a plasma density of 3 × 1013 cm−3 the magnetosonic modes excited by the beam become critically damped and the observed beam stopping length is in agreement with the theory. The calculated beam energy deposition agrees reasonably well with the measured value. A field reversal of 2 with changes in the magnetic field of 3.2 kG that last for 1 μs is observed at a density of 1013 cm−3.