Work

Time-dependent probability density functions and information geometry in a stochastic prey–predator model of fusion plasmas

Year: 2024

Type: article

Abstract: A stochastic, prey–predator model of the low to high confinement transition is presented. The model concerns the interaction of a turbulent fluctuation amplitude, zonal flow shear, and the ion density gradient. Delta-correlated noise terms are used to construct Langevin equations for each of the three variables, and a Fokker–Planck equation is subsequently derived. A time-dependent probability distribution function is solved and a number of diagnostic quantities are calculated from it, including the information rate and length. We find the marginal probability distribution functions to be strongly non-Gaussian and frequently multi-modal, showing the coexistence of dithering and H-mode solutions over time. The information rate and length are shown to be useful diagnostics to investigate self-regulation between the variables, particularly the turbulence and zonal flow shear.

Source: Physics of Plasmas

DOI: 10.1063/5.0193622

Authors: Patrick Fuller, Eun-jin Kim, Rainer Hollerbach, Bogdan Hnat

Institutions: University of Warwick, Coventry University, Seoul National University, University of Leeds

Language: English

Topic: Magnetic confinement fusion research

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Funders: National Research Foundation, Seoul National University, National Research Foundation of Korea, Ministry of Science and ICT, South Korea

Award: G1368267253