NASC-117Satellite Experiment:Measurement of the Nonlinear Impedance and Nonlinear Plasma Effects in the Near Field of an Electric-Dipole Antenna.

摘要

The nonlinear impedance of a satellite-borne,electric-dipole antenna was measured at ELF/VLF at drive voltages between 10mV and 100 V peak-to-peak. The magnitude of the impedance is in general agreement with the predictions of theoretical models of plasma-clad antennas. At the higher drive voltages the magnitude of the impedance is a weak function of electron density. The magnitude decreases as electron density increases. At low voltages the phase angle of the impedance is in agreement with linear sheath models. As the voltage increases the phase angle rotates through 0deg in the inductive sense. Above 10 V p-p the phase angle often exceeds +90deg. The electric and magnetic field intensities measured in the near field of the primary dipole are presented as a function of frequency,drive voltage,and electron density. (Author)