Relationship between auroral substorms and the occurrence of terrestrial kilometric radiation

The paper examines the correlation between magnetospheric substorms as inferred from the AE(11) index and the occurrence of terrestrial kilometric radiation (TKR) as observed by the Goddard radio astronomy experiment on board the Imp 6 spacecraft. It is suggested that many TKR events begin at low altitudes and high frequencies (approximately 400 - 500 kHz) and spread to higher altitudes and lower frequencies as the substorm expands. AE and TKR are well correlated for observations in the 1500-300 MLT zone and poorly correlated for the complementary zone. High-resolution dynamic spectra obtained during periods of isolated substorms are described; the substorm expansion phase corresponds to a rapid intensification and bandwidth increase of TKR.