Coronal composition above the solar equator and the north pole as determined from spectra acquired by the SUMER instrument on Soho

Citation
U. Feldman et al., Coronal composition above the solar equator and the north pole as determined from spectra acquired by the SUMER instrument on Soho, ASTROPHYS J, 505(2), 1998, pp. 999-1006
Citations number
42
Categorie Soggetti
Space Sciences
Journal title
ASTROPHYSICAL JOURNAL
ISSN journal
0004637X → ACNP
Volume
505
Issue
2
Year of publication
1998
Part
1
Pages
999 - 1006
Database
ISI
SICI code
0004-637X(19981001)505:2<999:CCATSE>2.0.ZU;2-Q
Abstract
Using spectra obtained by the SUMER instrument on the Solar and Heliospheri c Observatory (SONO) we have determined the composition of the bulk of the coronal plasma in the vicinity of the solar surface over a polar coronal ho le and an equatorial region. Our measurements show that although low first ionization potential (FIP) elements are enriched by about a factor of 4 in the corona above the quiet equatorial region, little or no enrichment exist s above the north polar coronal hole. These observations are in good agreem ent with the Ulysses in situ observations in both fast speed and slow speed winds.