Near-surface atmospheric electric field changes through magnetic clouds via coronal mass ejections

The Earth’s electrical environment is influenced by both external and internal driving factors. Internal driving factors include the global charging current produced by lightning storms, global aerosol concentrations and cloud coverage. External factors are caused by various space weather phenomena, including changes in the Sun’s magnetic field, solar flares, coronal mass ejections, and ionization changes from high-energy particles from the Sun and galactic cosmic rays. This study focuses on the cosmic ray intensity changes observed at the OULU Station and the vertical atmospheric electric field changes observed at the Azores and Studenec stations during a solar activity event in September 2017. The results indicate that the atmospheric electric field at the two stations (Azores and Studenec) simultaneously decreased by 80% and 120% of the mean atmospheric electric field value, respectively, during the same time as the significant decrease in cosmic ray intensity. The linear correlation coefficient between the decreased atmospheric electric field measured at these two stations was 0.60, indicating a global effect from the shocks and magnetic clouds associated with coronal mass ejections on atmospheric electricity. Finally, this study describes shock waves and magnetic clouds that impede the propagation of galactic cosmic rays, resulting in a decrease in ionospheric potential and atmospheric electric field.