Non-Linear Time Series Analysis Methods and Their Application to Fluctuation Data From Plasma Experiments

• Author / Creator

  Gnanasekaran, Aparajit

• Non-linear fluctuations are a common feature of data extracted from plasma experiments
  and are common in the edge regions of magnetically confined plasmas where
  long filament-like structures of density and temperature can generate them. These
  fluctuations are associated with turbulence and vortices leading to complex chaotic
  transport in these regions. Hence, the analysis of these fluctuations are important
  due to the applications of plasma confinement in research like nuclear fusion.
  Non-linear time series are present in many fields of research such as atmospheric
  sciences, neuroscience, finance, seismology and more. Hence, methods to understand
  non-linear dynamics has been of utmost importance to researchers. One of the main
  outcomes of non-linear time series analysis is to identify the nature of the time series
  as periodic, chaotic or stochastic. There have been many methods developed to
  perform this analysis from well established methods such as Lyapunov exponents to
  newly developed methods such as multifractal analysis.
  The following thesis explores three methods of non-linear time series analysis:
  CH-Plane method, Hurst exponent and Lyapunov exponent. CH-Plane is a newly
  developed method to identify whether a time series is based on underlying dynamics
  of a deterministic or stochastic nature. Hurst exponent is a well known quantifier for
  the memory of a system. Lyapunov exponent is the most commonly used quantifier
  for the degree of chaotic nature in a system. These methods are used to analyze Ion
  Saturation Current and Floating Voltage fluctuation data from a plasma experiment
  focusing on cross-field transport fluctuations associated with temperature filaments
  in cold plasma background. Through this, the thesis shows the breadth of non-linear
  time series analysis methods available to researchers and their applications in plasma
  research.

• Subjects / Keywords

  • Plasma Physics
  • Non-Linear Time Series Analysis
  • CH-Plane

• Graduation date

  Fall 2023

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-aydc-a811

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.