Authors: Jacob McLaughlin (University of Iowa), Fred Skiff (University of Iowa)

Neutral calcium plasma is particularly interesting for studies of ion wave dynamics. Apart from the Barium Q-machine, laser induced fluorescence (LIF) measurements in most contexts rely on excitation from metastable states.  However, under many circumstances involving inhomogeneous plasma or large perturbations, the metastable distribution function may be very different from the total ion distribution and may even be closer to the neutral atom velocity distribution.  Achieving ground-state LIF in most plasmas (e.g.  He, Ar) requires pump laser frequencies on the order of petahertz, which is currently unfeasible.  In calcium, this can be achieved with a tunable diode laser operating at several hundred terahertz by pumping the 3p64s 2S1/2 to 3p64p 2P01/2 transition (397nm) and observing emission as the ion deexcites to the 3p63d 2D3/2 state (854 nm). Presented is a novel plasma source designed for producing ionized calcium. Neutral gas (Ar, Xe, Ca, etc.) is passed through a cylindrical cavity where the TE111 mode is excited.  Ionization efficiency is increased by external permanent magnets tuned for electron cyclotron resonance (ECR) at the cavity mode frequency. Ionization has been sustained in argon and xenon with as little as 100mW rf power at the antenna. The permanent magnetic field profile has been adjusted to allow extraction of the plasma from the source, which will be characterized with a Langmuir probe, microwave interferometry, and various LIF diagnostic techniques.