Enhanced Escaping Terrestrial Continuum Radiation and Kilometric Continuum Radiation Observations and Implications

Enhanced escaping terrestrial continuum radiation has been shown to be due to injected electrons from the plasmasheet drifting around the earth eastward and impinging on portions of the plasmasphere and magnetosphere where steep density gradients occur. Electrostatic emissions at the local electron plasma frequency are mode converted to electromagnetic radiation that propagates out unless or until it encounters a region more dense than where it was generated. Kilometric continuum radiation in the 100 kHz to 800 kHz frequency range first found in the GEOTAIL Plasma Wave Instrument (PWI) data has been believed to be due from a similar source mechanism but from much deeper within the plasmasphere. Both types of emissions contain much narrowband filamentary and fine structure. Narrowband filaments lasting many hours have been observed. The WIND Radio Science Experiment (WAVES) when near the Earth also frequently detects these emissions. By comparing the appearance of these emissions from two or more spacecraft we are able to deduce remotely the structure of the plasmasphere and magnetosphere. Some of the structure observed can be explained by the bulges, ducts, and irregularities known to exist in the plasmasphere. Comparisons of wave data from GEOTAIL and wave and imaging data from IMAGE indicated that some kilometric continuum events have their source in density bite-outs deep within the plasmasphere. Some of these bite-outs appear to last for several days as had previously been deduced from ISEE and CRRES number density measurements.