Ionospheric slab thickness during geomagnetic storms

The relationship between ionospheric slab thickness and the physical parameters of the ionosphere during magnetic storms has been obtained from measurements of total electron content (at Hamilton, Massachusetts, 1967-1972) and of maximum electron density (Fort Belvoir, 1967-1968 and Wallops Island, 1968-1972). Positive and negative phases of the storms were computed for day and night periods; about 75% of the positive phases were found to occur during daytime while about 75% of the negative phases occurred at night. The magnitude of the positive phase increased with storm intensity while the negative phase was independent of storm intensity. The O(+)-H(+) transition height experiences a reduction from the quiet level during daytime as a result of the storm.