Velocity space degrees of freedom of plasma fluctuations

The study of plasmas, loosely defined here as ionized gases, is a rich field of both experimental and theoretical methods. This thesis introduces a new measurement technique for measuring the dynamics of plasmas at a localized point. It accomplishes this by measuring, simultaneously, plasma ion populations with two different velocities in the same small physical volume. This is done with laser spectroscopy, which can measure classical quantities like velocity or position without affecting them.

This measurement opens a new parameter space in experimental plasma physics. Theoretical methods for analyzing and interpreting this measurement do not exist or are poorly developed. This thesis, in addition to introducing the measurement itself, presents some analysis methods and begins the interpretation of the resulting modes from these data. Analyzing this measurement and developing theory to interpret it more is a rich avenue of future work.

Through this local measurement, small scale waves in plasmas can be investigated. These small scale waves are a current research subject in fusion plasmas, astrophysical plasmas, and basic plasma physics experiments. This measurement technique may be a useful tool for detecting, characterizing, and investigating these modes.