Ionospheric Response to the Coronal Hole Activity of August 2020: A Global Multi‐Instrumental Overview. Issue 12 (27th December 2022) - Younas, Waqar
Abstract: We have studied the ionospheric response to a coronal hole event of August 2020 using the data from global ionospheric maps, ground magnetometers and parameters from the instruments onboard SWARM and thermosphere, ionosphere, mesosphere energetics and dynamics satellites. The role of different physical drivers, responsible for observed ionospheric disturbance, has been identified. On the storm day (2 August), a steady southward directed interplanetary magnetic field B z caused the penetration of magnetospheric convection electric field and positive storm effect in daytime sectors. As a result of prompt penetration electric field (PPEF) on 2 August, a polar‐ward expansion of day‐side ionospheric plasma. On 3 August, the signatures of both disturbance dynamo electric field (DDEF) caused by disturbed thermospheric winds and PPEF have been observed. The westward PPEF and eastward disturbance DDEF on the night‐side caused a strong enhancement in ionospheric plasma parameters at the corresponding sectors. The effect of disturbed thermospheric winds and resultant electric field persisted till the end of 7 August. The large decrease in O/N2 ratio at northern mid‐latitudes which is a consequence of the seasonal impact resulted in the negative storm effects at corresponding latitudinal regions. This study has shown that although the storm of August 2020 was a minor one, the associated high speed solar wind streams emanating from a coronal hole resulted in drastic changes in ionospheric parameters including global electron content, in situ electron density and total electron content at the equatorial ionization anomaly and equatorial electric field. Plain Language Summary: Coronal holes are regions on the surface of sun with open magnetic fields. Such regions are associated with high speed solar winds which can significantly disturb the quiet‐time ionosphere. In this work we studied the ionospheric disturbance as generated by coronal hole activity of August 2020 using the data from ground and space borne instruments. We have identified the role of various physical drivers which have been active during this particular space weather events. The signatures of penetrating electric fields, disturbance dynamo, and composition changes are found in this activity. This study highlight that such coronal hole activities can also perturb the ionospheric parameters. Hence, the modeling community should also take into account the role of such drivers while forecasting the ionospheric parameters. Key Points: Ionospheric response to coronal hole event of August 2020 is analyzed using ground and space borne instruments The prompt penetrating electric field has seen to cause a pole‐ward expansion of the day‐side ionospheric plasma on 2 August Seasonal effects in disturbed winds have caused negative storm effect in the summer hemisphere