Effect of electric field on low-latitude storm time ionospheric foF2 variations

The electric field plays an important role in low-latitude ionospheric evolutions. Taking two major storms in October-November 2003 for example, the effects of plasma transportation, which is caused by equatorial disturbance electric field, on low-latitude storm time ionospheric variations at given locations were studied near 105°E. The theoretical model of SAMI2 was used to simulate these two events. It is shown that the electric field can cause complicated variations on the ionospheric foF2. For the isolated storm during 19~24 November, the disturbance field dominated the ionospheric variations during the initial phase. The upward/polarward plasma drift caused a negative storm at Haikou and a positive one at Chongqing and Lanzhou, respectively. The former and the latter two are on either side of the north crest of equatorial ionospheric anomaly. For the seriate storms during 28 October-2 November, the influence of the electric field was major at the beginning, while both the field and the neutral composition act on the ionosphere subsequently, leading to complex disturbances. The disturbance field can cause immediate responses on the ionosphere, though the latter can last longer. The results shown here is of importance to zonal short-time ionospheric predictions.