Highly relativistic radiation belt electron acceleration, transport, and loss: Large solar storm events of March and June 2015.

Two of the largest geomagnetic storms of the last decade were witnessed in 2015. On 17 March 2015, a coronal mass ejection-driven event occurred with a (storm time ring current index) value reaching -223 nT. On 22 June 2015 another strong storm ( reaching -204 nT) was recorded.