The study of ionospheric responses to magnetic storms in the Asian-Pacificregion

The effects of magnetic storms in the midlatitude and low-latitude ionosphe re has been studied based on data of the ionopsheric stations located betwe en 90 degrees and 160 degrees E and at geomagnetic latitudes from 51 degree s N to 69 degrees S. Intense magnetic storms observed at different levers o f solar activity in equinox conditions are considered. It has been shown th at the main effects of the considered storms are as follows: (I) prolonged intense negative disturbances at subauroral and mid-latitudes at the phases of storm development and recovery; (2) delay in the development of the f(0 )F2 disturbance with decreasing latitude; (3) variations in the amplitude o f f(0)F2 deviations at low latitudes, which had started at latitudes corres ponding to L = 1.5; (4) mostly negative disturbances in the solar activity maximum and both negative and positive disturbances in the minimum of solar activity; and (5) positive disturbance in the dusk sector before a negativ e phase at subauroral and midlatitudes, which can be explained by the proce sses forming the main ionospheric trough early in the evening.