  Are critical points important in the Solar Probe Mission? This is a brief
discussion of the nature of critical points in solar wind models, what this
means physically in the 'real' solar wind, and what can be expected along a
nominal Solar Probe Orbit. The conclusion is that the regions where the wind
becomes transonic and trans-Alfvenic, which may be irregular and varying, may
reveal interesting physics, but the mathematically defined critical points
themselves are of less importance.
