Atomic lifetime measurements of Ne-like Fe ions in a magnetic field

Abstract Among the lowest excited levels in Ne-like ions, that is, of configuration 2p 5 3s, there is a J = 0 level that in a field-free environment decays by a magnetic dipole (M1) transition to the lower J = 1 level of the same configuration only. In the presence of a magnetic field, this level can also decay to the ground configuration J = 0 level. In the course of the first measurement of the 2p 5 3s J = 0 level lifetime and the M1 transition rate the magnetically induced transition (MIT) appeared as a complication that was then turned into a tool. The technical details of the measurement in an electron beam ion trap have been described elsewhere. Here we illuminate the physics aspects of the two transition rate measurements and show how the results compare to computations.