Open AccessExtreme ultraviolet emission lines of Ni xii in laboratory and solar spectra
Author(s) -
Keenan F. P.,
Botha G. J. J.,
Matthews A.,
Lawson K. D.,
Coffey I. H.
Publication year - 2000
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2000.03600.x
Subject(s) - physics , emission spectrum , spectral line , extreme ultraviolet , ultraviolet , wavelength , line (geometry) , astrophysics , solar flare , astronomy , optics , laser , geometry , mathematics
Wavelengths for emission lines arising from 3s 2 3p 5 –3s3p 6 and 3s 2 3p 5 –3s 2 3p 4 3d transitions in Ni xii have been measured in extreme ultraviolet spectra of the Joint European Torus (JET) tokamak. The 3s 2 3p 5 2 P 1/2 –3s 2 3p 4 ( 3 P)3d 2 D 3/2 line is found to lie at 152.90±0.02 Å, a significant improvement over the previous experimental determination of 152.95±0.5 Å. This new wavelength is in good agreement with a solar identification at 152.84±0.06 Å, confirming the presence of this line in the solar spectrum. The Ni xii feature at 152.15 Å may be a result only of the 3s 2 3p 5 2 P 3/2 –3s 2 3p 4 ( 3 P)3d 2 D 5/2 transition, rather than a blend of this line with 3s 2 3p 5 2 P 3/2 –3s 2 3p 4 ( 3 P)3d 2 P 1/2 , as previously suggested. Unidentified emission lines at 295.32 and 317.61 Å in solar flare spectra from the Skylab mission are tentatively identified as the 3s 2 3p 5 2 P 3/2 –3s3p 6 2 S 1/2 and 3s 2 3p 5 2 P 1/2 –3s3p 6 2 S 1/2 transitions in Ni xii , which have laboratory wavelengths of 295.33 and 317.50 Å, respectively. Additional support for these identifications is provided by the line intensity ratio for the solar features, which shows good agreement between theory and observation.