The response of geomagnetic spectral composition to solar wind during storm time

In this paper 16 geomagnetic storms in 1968-1978 recorded at 8 magnetic observatories located from polar to equatorial regions in the lambda=1200E longitudinal zone and its vicinity have been analysed. The horizontal component H traces of 27 h interval have been sampled once every 1.5 min. The time sequences of the data thus obtained have been processed by the method of digital filtering and maximum entropy spectral analysis (MESA). The results of the analysis are compared with the associated solar wind parameters. It confirms that the geomagnetic disturbances are controlled by the solar wind in several ways, i.e. geomagnetic disturbances respond differently to various solar wind parameters or to the different ranges of Bsub(z). The north-south component of the interplanetary magnetic field (IMF) Bsub(z), the IMF latitude theta and the solar velocity V play the most important part in inducing geomagnetic storms. (author)