Low-latitudinal ionospheric effects during a moderate storm by tomographicimaging

In this paper computerized ionospheric tomographic technology has been appl ied to investigate low-latitudinal ionospheric behavior during a moderate m agnetic storm. From CT reconstructed imaging, during the main phase and rec over phase both of positive and negative storm phases in low latitudinal io nosphere are seen and they are not only latitude dependent but also height dependent. It is certainly identified that a deep depletion in electron den sity occurred just about 20 minutes after ssc at geomagnetic latitudes arou nd 10 degrees where equatorial anomaly crest seats usually. The depleted ho le extends over both the bottom and top F-region, with a steep wall on its equatorial side. This is a very interesting low-latitude ionospheric respon se to initial phase of storm and worthy of further study.