ISEE-1 SATELLITE OBSERVATIONS OF VLF SIGNALS AND ASSOCIATED TRIGGERED EMISSIONS FROM THE SIPLE STATION TRANSMITTER

摘要

During the International Magnetospheric Study (IMS), the ISEE-1 spacecraft has been an important component of VLF wave-injection experiments for studying interactions between coherent VLF waves and energetic particles. The coherent waves are injected into the magnetosphere by ground-based transmitters such as that at Siple Station, Antarctica, and those of the worldwide Omega navigation network. In this paper, we report on data acquired by the Stanford VLF receiver on ISEE-1 during the period October 1977-August 1979. The results show that the transmitter signals, propagating in the nonducted mode, are observed continuously over large regions of the plasmasphere. VLF emissions triggered by the nonducted waves generally are found to possess spectral characteristics different from those of emissions triggered by ducted signals.