Rocket-induced lower ionosphere disturbances derived from measurements of very low frequency transmitter signals

A rocket launch can induce large-scale atmospheric disturbances, which have mainly been investigated in previous studies by using measurements of total electron content. In this study, we report the perturbation in very low frequency (VLF) transmitter signals triggered by a rocket launch event, which, unlike total electron content measurements, is directly related to the D-region ionosphere. The perturbation in VLF measurements typically occurred ~9 min after liftoff, resulting in an amplitude change of up to 2.82 dB, and it had a common period of ~3.5–7 min. Moreover, the perturbation consisted of two isolated pulses, a feature notably different from previous measurements. Given the close correlation between the rocket launch and the VLF measurements, as well as the similarity between different propagation paths, these perturbations were likely caused by shock acoustic waves generated during the rocket launch because the periods were similar.