Is the Electron Strahl in the Solar Wind a Seed Population for the Earth’s Electron Radiation Belt?

The electron strahl is a population of field-aligned electrons with energies of 100s–1000s of eV moving outward from the corona along the interplanetary magnetic field. Depending on the toward-versus-away nature of the interplanetary magnetic field, the Sun’s corona magnetically connects to the Earth’s southern-versus-northern polar cap, where the strahl electrons produce the polar-rain aurora in the connected polar-cap atmosphere. Solar-wind magnetic-field lines connected to the polar caps eventually are captured into the Earth’s magnetotail via nightside reconnection, and some of those captured field lines (north or south) have the active strahl on them. A critical question: Is the magnetotail’s observed suprathermal electron population comprised of strahl electrons? When a magnetospheric substorm occurs, the suprathermal electron population of the magnetotail is energized and delivered into the nightside dipolar magnetosphere as the “substorm-injected-electron” population with 10s–100s of keV. It is commonly believed that this substorm-injected-electron population becomes the electron radiation belt via energization in the dipolar magnetosphere by whistler-mode chorus waves. The full question stated backwards is: Were the radiation-belt electrons once strahl electrons from the solar corona?