Physical Properties of Polar Coronal Rays and Holes as Observed with the Spartan 201-01 Coronagraph

Abstract

Physical conditions and characteristics of polar coronal rays and polar coronal holes are derived from white-light coronal observations aboard the Spartan 201-01 spacecraft and the ground-based K-coronameter in Mauna Loa, Hawaii, on 1993 April 11-12. An array of polar rays extending from 1.16 to 5.0 R☉ was observed in both the north and south polar coronal hole regions. They appear as coherent structures at much higher altitudes than previously observed. Densities and scale height temperatures are estimated as a function of radial height for the holes and the rays. These profiles suggest that there is extended heating up to heights of 1.4-2.6 R☉.