The goal of this research is to explore how plasma, a gas made up of electrically charged particles such as electrons and ions, behaves when it is subjected to a particular electrical condition called a 'multipole field'. When a cloud of plasma is placed within a structure of several long, parallel metal rods with rapidly changing voltage applied to them, some of the plasma particles may be trapped at the center of the structure. This effect provides a laboratory test bed for conducting many new basic plasma physics experiments. The experiments will be performed along with computer simulations of the same phenomena to gain combined insight into the underlying physics of the collective interactions of the trapped particles. This project will take place in an environment that is accessible to undergraduate university students. The results and descriptions of the research will also be incorporated into outreach for physics in the greater Anchorage community. In particular, the research will create a centerpiece demonstration of plasma science on-site at the University of Alaska - Anchorage to provide formative encounters for K-12 students, and positive engagement with the community at large.
This research is a computational and experimental study of the behavior of low-temperature, quasi-neutral plasma in a three-dimensional, time-varying electric multipole field. Theoretical work done previously on this topic raised questions that point to the need for such simulations and experiments. Computer simulations will study the effect of the plasma species' mass difference on the plasma response, e.g. the multipole field's ability to focus the light species to the center of the multipole structure while the space charge is neutralized by the heavy species. The results of computer modeling will inform an initial experimental design and study of the same effects. A resonant multipole structure will be constructed and installed in an ultra-high vacuum chamber and experimental measurements of the plasma in the multipole will be made for comparison to the computational results. The laboratory setup will serve as a versatile testbed for ongoing studies in basic plasma physics, including: plasma effects on ponderomotive gyroresonance; formation and dependences of the radio frequency plasma sheath with variation of the plasma and external field characteristics; the effect of neutralizing space charge on plasma density; and radiation pressure effects on the plasma boundary.
