Atomic level lifetimes have been measured on magnetic dipole $\mathrm{}\left(M1\mathrm{}\right)\mathrm{}$ transitions in Si-like, P-like, Ar-like, K-like, and Ca-like ions of Kr, using an electron-beam ion trap in magnetic trapping mode. The lifetimes are compared to various predictions, including the results of different calculations. In Ar-like ions, magnetic quadrupole $\mathrm{}\left(M2\mathrm{}\right)\mathrm{}$ transitions have been identified as significant competing decay channels.

• Received 17 February 2001

DOI:https://doi.org/10.1103/PhysRevA.64.042511