Fabry-Perot spectroscopy of a visible magnetic dipole transition in Ba34+

We are using Fabry-Perot interferometry to study visible lines from highly-charged ions created and trapped within an electron beam ion trap (EBIT). The 3d(4) D-5(2)-D-5(3) titanium-like barium (Ba34+) line at 3932(2) Angstrom was recently measured in Ref. [1] (C.A. Morgan et al., Phys. Rev. Lett. 74 (1995) 1716) using a grating monochromator. We present preliminary Fabry-Perot spectra of this line with significantly improved resolution. The Doppler-broadened 1 Angstrom line width is consistent with an expected ion temperature of less than 1 keV. We discuss the possibility of resolving Zeeman splittings, and of using these visible lines as a diagnostic in high temperature, low density plasmas, like those that exist in tokamaks and the EBIT itself.