Electrostatic emissions with four different characteristics have been observed at or very near the electron gyrofrequency in broadband VLF data from the SCATHA satellite. The most common emission is sporadic, has a very narrow bandwidth, and occurs at the electron gyrofrequency. A second type is broadband, typically centered above the electron gyrofrequency, but extends down through the gyrofrequency. A third type has an attenuation band at the gyrofrequency with narrow bands of emissions above and below the gyrofrequency. The fourth type is broadband with a sharp lower-frequency cutoff at the electron gyrofrequency. These emissions tend to occur at high L values on the nightside of the magnetosphere. They also tend to occur away from the magnetic equator. |