Ionospheric Slab Thickness during Geomagnetic Storms

Abstract

The relationship of ionospheric slab thickness (<img src='/image/spc_char/tow.gif' border=0>) obtained from measurement of TEC at Hamilton (lat. 42·6° N; long. 708° W) and N_max at Fort Belvior (lat . 38·7° N; long. 77·1° W) and Wallops Island (lat. 37'9° N; long 75·5° W) during geomagnetic storms, with the physical parameters of the ionosphere has been investigated in comparison to the pre-storm level. Positive and negative phases of the storms are computed during day and night. About 3/4th of the positive phases occur during daytime while about 3/4^th of the negative phases occur at night. Magnitude or the positive phase of the storm is found to have increased with the strength of the storm but negative phase does not show any dependence on the strength of the storm. The O⁺->H⁺ transition height (<i>h_T</i>) is found to be lowered from the quiet level during daytime due to the storms. The electrons to ions temperature ratio <i>T_e/T_i</i> remains the same as the pre-storm value during daytime unless the storm is very intense.