Study of field aligned current (FAC) with D-component (east-west)and interplanetary electric field (Ey) during three different HILDCAA events

English Abstract:

Field Aligned Currents (FACs) play an important role for the coupling between ionosphere and magnetosphere. This coupling is directly influenced by solar wind and interplanetary magnetic field (IMF). In this work we observe characteristics of FACs during HILDCAAs (High-Intensity, Long duration, Continuous AE activity) by using high resolution OMNI data set consisting of 1-min averaged ACE, Wind, IMP 8 and Geo-tail magnetic field. We also observe the perturbations in the ∆D (east-west) component of the geomagnetic field from the low latitude station (Vassouras) to predicate the field aligned currents. For three different HILDCAA events, the characteristics of FACs and perturbations in the ∆D component observe are quite dissimilar. The wavelet techniques (CWT, DWT and wavelet modulus correlation) and cross-correlation also show different results for each event. The times and frequencies resolution of FAC and ∆D obtained from CWT are different in each event. The nature of square wavelet coefficients obtain from DWT for FAC and ∆D are totally different. Both FAC and ∆D show good wavelet modulus correlation with components of interplanetary magnetic field (By and Bz) at the time of HILDCAA. We also observe the cross-correlation between FAC and ∆D, FAC and Ey and Ey and ∆D. During the non-storm HILDCAA, FAC shows negative correlation with ∆D. But it shows positive correlation for CIR and ICME preceding HILDCCAs. Similary, Ey and FAC also show negative correlation during non-storm HILDCAA but other two events show positive correlation. Finally, Ey and ∆D show positive correlation for all events. Observing these results, it can be suggested that the ground magnetic datasets obtained from low latitude may serve as the proxy for interplanetary conditions in the solar wind.