The Entropy and Complexity of Drift waves in a LAPTAG Plasma Physics Experiment
POSTER
Abstract
Drift waves grow from noise on a density gradient in a narrow (dia $=$ 3 cm, L $=$ 1.5 m) magnetized ( B$_{oz} = $ 160G) plasma column. A two-dimensional probe drive measured fluctuations in the plasma column in a plane transverse to the background magnetic field. Correlation techniques determined that the fluctuations were that of electrostatic drift waves. The time series data was used to generate the Bandt-Pompe/Shannon entropy, H, and Jensen-Shannon complexity, C$_{JS}$. C-H diagrams can be used to tell the difference between deterministic chaos, random noise and stochastic processes and simple waves, which makes it a powerful tool in nonlinear dynamics. The C-H diagram in this experiment, reveal that the combination of drift waves and other background fluctuations is a deterministically chaotic system. The PDF of the time series, the wave spectra the spatial dependence of the entropy wave complexity will be presented. LAPTAG is a university-high school alliance outreach program, which has been in existence for over 20 years.
*Work done at BaPSF at UCLA and supported by NSF and DOE.