X-ray-line diagnostic of magnetic field strength for high-temperature plasmas

An x-ray line diagnostic for use in magnetic field measurements in high-temperature plasmas has been identified. The intensity of the otherwise strictly forbidden 1s(2)2s(2)2p(1/2)2p(3/2)(4)3s(1/2) (3)P(0) --> 1s(2)2s(2)2p(6) (1)S(0) transition in neonlike ions is shown to depend on the magnetic field strength. The field dependence is illustrated between one and 3 T in the Ar(8+) spectrum. The line is well resolved, bright, and close to reference lines, making it an experimentally simple to use diagnostic.