Ring current is largely carried by ions in the 20-200 keV energy range
Ring current plasma is believed to come from both the solar wind and the ionosphere
- Insitu measurements have found O+ is larger than H+ in large storms
- O+ indicates ionospheric origin, H+ can be both ionospheric or solar wind
Questions that remain to be answered
- What is the origin of the ring current ions?
- What are the mechanisms for energization and transport into the ring current region (L=2-7 Re)?
- What are the mechanisms for the loss of the ring current during the storm recovery phase?