The transition from slow to fast solar wind: Charge state composition and electron observations

Abstract

The charge state composition is a very sensitive measure for the electron properties at around 2 solar radii heliocentric distance. Even though the basic principle of the charge-state freeze-in process is rather well understood, it is not clear how the non-thermal properties of the electron distribution functions influence the frozen-in charge states. The obvious question to ask, then, is whether in situ electrons exhibit the same temporal variations as the charge state composition. Using SWICS/ACE and 3DP/WIND data, we find that the core electrons are dominated by local effects like compression and have no memory of their coronal origin. Supra-thermal electrons, on the other hand, show a clear correlation with the charge state data. © 1999 American Institute of Physics.