Radiation belt electrons respond to multiple solar wind inputs

We find that the solar wind bulk speed tends to be the primary driver of electron flux enhancements at magnetic L shells larger than 4, with little or no relation to flux decreases. Changes in the solar wind's magnetic field strength tend to temporarily reduce electron fluxes between L = 4 and L = 8, while enhancing it between L = 3 and L = 4. In contrast to predictions generated by single-input linear filters, multi-input filters show that solar wind plasma density only contributes weakly to electron flux variability, although it does so consistently across nearly all L shells.

Finally, we studied two distinct 4-year intervals within the most recent solar cycle and found that smaller, more time-stationary prediction errors are generated by multi-input linear filters. We therefore conclude that multi-input filters more accurately reflect real dynamic relationships than any single-input linear filter alone.