Flow properties of the solar wind derived from a two‐fluid model with constraints from white light and in situ interplanetary observations

Abstract

We derive the flow properties of the solar wind in coronal holes using a two‐fluid model constrained by density profiles inferred from simultaneous space‐based SPARTAN 201–01 and ground‐based Mauna Loa White Light coronagraph observations, and by in situ interplanetary measurements. Also used as a guide is the hydrostatic temperature profile derived from the density gradient. Density profiles are inferred between 1.16 and 5.5 R s , for two different density structures observed along the line of sight in a polar coronal hole. The model computations that fit remarkably well the empirical constraints yield a supersonic flow at 2.3 R s for the less dense ambient coronal hole, and at 3.4 R s for the denser structures. The novel result that emerges from these fits is a proton temperature twice as large as the electron temperature in the inner corona, reaching a peak of 2 × 10 6 K at 2 R s .