Geomagnetic Field Effects Over the Philippines During Strong Solar Flares in April 2022

During solar storms, conductivities in Earth’s ionospheric regions become more enhanced. This phenomenon produces effects on Earth’s current systems to which emissions of solar radiation largely contribute. Such radiations are analyzed as short timescale variations of the X-ray and EUV fluxes. This was observed for the two X- and three M-class solar flares on 17, 20, and 21 April 2022. All of which are geomagnetically quiet days with nominal Kp, Hp, and Dst indices. Magnetic responses were observed from magnetometers in the Philippines, located in the low-latitude (MUT) and near-equatorial (DAV) stations. These coexisting variations observed with Earth’s magnetic field are referred to as magnetic crochets. Measurements also showed that solar flare effects (Sfe) are more pronounced near the equator, where high conductivity generates more variations in Earth’s magnetic fields. Yet, the largest variations were not consistently observed for the strongest flares. At MUT, manifest variations in \(H_{{\text{sfe }}}\) (horizontal) and \(Z_{{\text{sfe }}}\) (downward) were aligned with the X1.1 and M1.89 flares on day 17. Variations are generally homogeneous on days 20 and 21. Meanwhile, the largest variations at DAV were found during the M9.7 flare on day 21. It is inferred that increases in \(H_{{\text{sfe }}}\) remain greater than in \(Z_{{\text{sfe }}}\) at both stations. Fluctuations in \(H_{{\text{sfe }}}\) are nonetheless more prolonged and heightened at DAV station.