Limitations on suprathermal tails of electrons in the lower solar corona

Abstract

Measurements of the charge states of solar wind ions by the SWICS instrument on Ulysses are used to place limits on the extent to which the velocity distribution of electrons in the lower solar corona deviates from a Maxwellian distribution by having a suprathermal tail. It is found that the data are consistent with a suprathermal tail which is not large, and which has a minor influence on the location and magnitude of the maximum of the electron temperature. This result has implications for theories which propose that suprathermal tails of electrons in the solar corona can have a strong influence on the formation of the solar corona and the dynamics of the solar wind.