The Variation of Ionospheric Slab Thickness at Thailand Equatorial Latitude Station

This paper presents the study and analysis of ionospheric slab thickness (τ) during the solar minimum in year 2006. The ionospheric slab thickness is obtained from the ratio of the total electron content (TEC) to the peak electron density in the F2 region (NmF2). According to the analysis of the total electron content and the peak electron density in the F2 region, the peak electron density in the F2 region by critical frequency (foF2) are determined by ionosonde technique. In addition, the total electron content are determined by the correlation of different time delay of 2 L - band signals from GPS satellites. All three parameters, critical frequency, total electron content, and peak electron density in the F2 region, are analyzed at the Chumphon campus King Mongkut’s Institute of Technology Ladkrabang station, located at longitude 99.3˚E and latitude 10.7 ˚N. The analyzed results show that there are irregularities of all parameters during the equinox period and the ionospheric slab thickness at low latitude peaks in the pre-sunrise.