Dependence of Coherence Scales of Ionospheric Scintillation Patterns on Magnetic Activity

Abstract

The amplitude scintillation data, recorded at 251 MHz by two spaced receivers at low latitude station Kolhapur [16.42oN, 74.2oE] are used. We have considered data of magnetically disturbed days (Ap[20) to investigate the effect of magnetic activity on the ionospheric irregularities by observing the coherence scales of the scintillation pattern produced by the irregularities. The coherence scales are calculated using the method introduced by Bhattacharyya et al. (2003). Coherence scale lengths on magnetically disturbed days are higher than that of on quiet days. During magnetically disturbed period the coherence scales in the post midnight period are greater than that of in the pre midnight period. This suggests that magnetospheric electric field generated in storm time causes increase in coherence scales but shows large increase after midnight.