Chaotic edge density fluctuations in the Alcator C-Mod tokamak

• Main Authors: Zhu, Z. (Author), Carter, T. A. (Author), White, Anne E. (Contributor), Baek, Seung Gyou (Contributor), Terry, James L (Contributor)
• Other Authors: Massachusetts Institute of Technology. Plasma Science and Fusion Center (Contributor)
• Format: Article
• Language: English
• Published: American Institute of Physics (AIP), 2018-07-24T18:49:53Z.
• Subjects: Article
• Online Access: Get fulltext

Analysis of the time series obtained with the O-Mode reflectometer [Rhodes et al., 1997 Plasma Phys. Controlled Fusion 40, 493-510 (1998)] and the gas puff imaging [Cziegler et al., Phys. Plasmas 17(5), 056120 (2010)] systems on the Alcator C-Mod tokamak reveals that the turbulent edge density fluctuations are chaotic. Supporting evidence for this conclusion includes the observation of exponential power spectra (which is associated with Lorentzian-shaped pulses in the time series), the population of the corresponding Bandt-Pompe probability distributions [Bandt and Pompe, Phys. Rev. Lett. 88, 174102 (2002)], and the location of the signal on the complexity-entropy plane (C-H plane) [Rosso et al., Phys. Rev. Lett. 99, 154102 (2007)]. The classification of edge turbulence as chaotic opens the door for further work to understand the underlying process and the impact on turbulent transport.
United States. Department of Energy (Grant DE-FC02-99ER54512)
United States. Department of Energy (Grant DE-FC02-07ER54918-011)