Geomagnetic Activity & the Effect of Tau X-Ion the D-Region

Abstract

Data from a 164 kHz long wave propagation experiment at Gulmarg are analyzed to study the effect of X-rays from Tau X-Ion the D-region ionization. Increased absorption of the 164 kHz waves, corresponding to increased ionization at the time of the transit of Tau X-lover the reflection point, is observed consistently during 1975-77. The absorption suffered by the radio waves at the time of the meridian transit of the source is shown to depend inversely on the level of geomagnetic activity, the absorption being negligibly small on magnetically disturbed days. This dependence of absorption on geomagnetic activity is explained as being due to a possible geomagnetic dependence of NO concentration at D-region heights.