Improved Method for Specifying Solar Wind Speed Near the Sun

Abstract

We have found an improved technique for empirically specifying solar wind flow speed near the Sun (∼0.1 AU) using a set of three simple inter‐linked coronal/solar wind models. In addition to magnetic field expansion factor, solar wind speed also appears to be influenced by the minimum angular distance that an open field footpoint lies from a coronal hole boundary. We conduct our study using polar field corrected Mount Wilson Solar Observatory Carrington maps from 1995. During this period, the Sun was in the declining phase of the solar cycle and the solar wind had relatively simple global structure.