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Measurements of coronal kinetic temperatures from 1. 5 to 3 solar radii

Journal Article · · Astrophys. J., Lett. Ed.; (United States)
DOI:https://doi.org/10.1086/183373· OSTI ID:6636044
A rocket-borne L..cap alpha.. coronagraph has been used to make the first measurements of the spectral line profile of resonantly scattered hydrogen L..cap alpha.. coronal radiation between 1.5 and 3 solar radii. These data provide, for the first time, direct measurements of coronal temperatures above 1.5 solar radii. Data were obtained in a coronal hole, quiet region, and streamer. The widths of the profiles from the quiet region decrease with height and correspond to a steady decrease in hydrogen kinetic temperature, with increasing radius, from about 2.5 x 10/sup 6/ K at rapprox. =2Rsun to about 10/sup 6/ K at rapprox. =4Rsun. In the coronal hole the measured line widths indicate a kinetic temperature of 1.8 x 10/sup 6/ K at rapprox. =2.5 Rsun.
Research Organization:
Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts
OSTI ID:
6636044
Journal Information:
Astrophys. J., Lett. Ed.; (United States), Journal Name: Astrophys. J., Lett. Ed.; (United States) Vol. 241:2; ISSN AJLEA
Country of Publication:
United States
Language:
English