In this project the student will select several (5 to 10) known substorm events from the year 2009 to year 2015 at mid-latitudes. Check geomagnetic storms behaviour for the corresponding sub-storm events using geomagnetic indices such as Dst and Kp. After the above identifications, the events will be analysed by determining the relationship between substorms and geomagnetic storms. Where after, the mechanism driving this sub-storm will also be investigate, e.g. magnetic reconnection. Additionally how technological systems are affected by sub-storms affect e.g. HF propagation, navigation.