2000 Articles

Experimental M1 Transition Rates of Coronal Lines from Ar X, Ar XIV, and Ar XV

Savin, Daniel Wolf; Trabert, E.; Beiersdorfer, P.; Utter, S. B.; Brown, G. V.; Chen, H.; Harris, C. L.; Neill, P. A.; Smith, A. J.

Transition probabilities of three magnetic dipole (M1) transitions in multiply charged ions of Ar have been measured using the Livermore electron-beam ion trap. Two of the transitions are in the ground configurations of Ar XIV (B-like) and Ar IX (F-like), and are associated with the coronal lines at 4412.4
and 5533.4 Ŏ , respectively. The third is in the excited 2s2p configuration of Be-like Ar XV and produces the coronal line at 5943.73 Å. Our results for the three atomic level lifetimes are 9.32^0.12 ms for the Ar X 2s22p5 2P1/2 level, 9.70^0.15 ms for the Ar XIV 2s22p level, and 15.0^0.8 ms for the Ar XVo 2P3/2o 2s2p level. These results diff†er significantly from earlier measurements and are the most accurate ones to date.