Relativistic electron acceleration due to an extreme fast solar wind stream
Abstract
Coronal holes on the Sun are a source of fast solar wind flowing out into the solar system. When they encounter the Earth's magnetosphere they are associated with some of the highest relativistic electron flux enhancements in the Earth's van Allen radiation belts and a special type of plasma wave known as chorus. Here we present a statistical analysis of chorus waves and show that for an event lasting 5 days the waves are strong enough to accelerate electrons and increase the flux greater than 2 MeV by 4 orders of magnitude. The flux increases rapidly but tends towards a plateau suggesting there is a limit to the acceleration. The flux remains high for several days even after the solar wind stream has passed. The flux level depends on the wave properties but is relatively insensitive to the presence of a pre-existing radiation belt. For satellites at geostationary orbit the flux results in a charging current that exceeds the NASA recommended guidelines for triggering an electrostatic discharge by more than a factor of 2. As a result, satellites at geostationary orbit are more at risk from a fast solar wind stream lasting 5 days or more than they are from an extreme geomagnetic storm.
- Publication:
-
42nd COSPAR Scientific Assembly
- Pub Date:
- July 2018
- Bibcode:
- 2018cosp...42E1489H