Student: Jacob McLaughlin, PhD student in Physic, University of Iowa
Faculty Advisor: Dr. Fred Skiff
Laser Induced Fluorescence of Calcium Ions Near a Boundary in a Multidipole Plasma Source
The research I perform with Dr. Fred Skiff at the University of Iowa focuses on studying fundamental plasma science. The characteristics and behavior of plasmas have implications in various applied fields, from plasma medicine to semiconductor development and especially the sun and its solar wind that bombards our magnetosphere, threatening our scientific spacecraft and the national power grid. The experiment I operate contains an electrode immersed in plasma, capable of being positive or negatively biased with respect to the plasma potential. Equipped with a diagnostic suite of probes and non-perturbative laser diagnostics, we study the plasma sheath region that forms when plasma meets a boundary and the many waves and instabilities that arise in these configurations. Sheath theory is a largely incomplete, yet often implemented, model of plasma-boundary behavior. Our time-resolved laser induced fluorescence (LIF) diagnostic affords us the unique capability of measuring ion instabilities that arise from the sheath region to better characterize the impact of plasma-boundary interactions.
Our current work involves transitioning to a plasma containing both calcium and argon ions in efforts to increase the fluorescence signal of our LIF diagnostic and probe the ground state energy levels of calcium. The ground state calcium ions better represent the overall ion behavior as opposed to the conventional probing of ions in excited metastable states, whose behavior is not necessarily representative of the overall ion population. These two benefits will allow improvements upon the study of sheath-region instabilities and advancements to the diagnostic techniques used to characterize the plasma under such conditions. For example, a novel method of tracking particles’ dynamics and interactions as they move through the plasma.