Comparison of Empirical Models for Polar and Equatorial Coronal Holes

摘要: We present a self-consistent empirical model for several plasma parameters of large equatorial coronal hole observed on 1999 November 12 near solar maximum. The was derived from observations with the Ultraviolet Coronagraph Spectrometer Solar and Heliospheric Observatory. In this Letter, we compare O VI λλ1032, 1037 emission lines previous polar minimum. At time observations, there no evidence holes. resulting describes outflow velocities most probable speeds O5+, compared ion properties minimum hole. comparison models shows that has lower O5+ perpendicular temperatures than its counterpart 1996 to 1997 at heights between 2 3 R☉. However, in situ asymptotic wind streams coming 1996-1997 are only ~15% different. Thus, bulk acceleration must occur above R☉ also higher density similar heights. It is not yet known whether densities responsible seeming inhibition fast extremely holes discuss constraints implications various theoretical heating acceleration.