Scientists have identified the systematic patterns of magnetic field and ionospheric currents in Antarctica and found that ionic currents are responsible for consistent magnetic field variations at both the Indian stations located in Antarctica- Maitri and Bharati. The results can be useful for space weather studies.

India operates two stations over Antarctica continent, viz. Maitri and Bharati. During geomagnetic quiet conditions, Indian Antarctic stations are considered to be located outside the auroral oval -- auroral oval' – a belt around the magnetic poles that expands or contracts depending on the strength of the solar wind. Maitri is equatorward and Bharati is poleward of the auroral oval. 

A team of scientists from the Indian Institute of Geomagnetism (IIG), an autonomous body of the Department of Science and Technology (DST) have examined the quiet time magnetic field patterns and associated ionospheric currents at these two stations from simultaneous observations at these two locations for 10-years (2013–2022).  

They have found that Maitri station exhibited a clear southern hemispheric solar quiet (Sq) type of magnetic field variation on geomagnetic quiet days in all seasons, indicating the influence of ionospheric dynamo due to thermospheric winds. Interestingly, Bharati station also displayed regular and systematic magnetic field variations.  Estimated equivalent ionospheric currents indicate strong equatorward/northward currents during all seasons at Bharati.

The study published in the Journal Polar Science shows that both stations showed annual type of seasonal variation with peak amplitude during summer and least during winter. The schematic illustration of global and polar Sqs proposed by the authors explains the results obtained through 10-years’ statistical study.

Figure 1: Statistical average of 10 years’ diurnal patterns at Maitri and Bharati stations along with the error bars.

Publication link: https://doi.org/10.1016/j.polar.2023.100979