Signatures of coronal hole spectra between 660 Angstroms and 1460 Angstroms measured with SUMER on SOHO

Citation
U. Schuhle et al., Signatures of coronal hole spectra between 660 Angstroms and 1460 Angstroms measured with SUMER on SOHO, SPACE SCI R, 87(1-2), 1999, pp. 299-302
Citations number
2
Categorie Soggetti
Space Sciences
Journal title
SPACE SCIENCE REVIEWS
ISSN journal
00386308 → ACNP
Volume
87
Issue
1-2
Year of publication
1999
Pages
299 - 302
Database
ISI
SICI code
0038-6308(1999)87:1-2<299:SOCHSB>2.0.ZU;2-M
Abstract
Spectra of the northern polar coronal hole measured with the SUMER spectrom eter on SOHO on 25 October 1996 are analyzed. We present spectra taken at l ocations on the solar disk where part of the spectrometer slit intersects a polar coronal hole region and an area of brighter emission from outside of the coronal hole area. By comparing the line intensities between the parts of the spectrum taken inside the "dark" area of the coronal holes and the brighter regions, we work out the signatures of the specific coronal hole i n the chromosphere, transition region and lower corona. We find that emissi ons of neutral atom lines, of which there are many in the spectrum of SUMER , show no difference between the coronal hole and the bright boundary areas , whereas all ionized species show strong intensity enhancements, including the continuum emissions of carbon and hydrogen. These enhancements are lar ger than in normal quiet Sun areas.