Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Spectral Entropy of Turbulence in a Fluid Model of Fusion Plasmas During a Low-To-High Confinement Transition
Submission Author:
Sarah Gomes da Silva Paes da Costa , DF , Brazil
Co-Authors:
Rodrigo Cerda, Ana Luiza Piragibe Freire
Presenter: Sarah Gomes da Silva Paes da Costa
doi://10.26678/ABCM.COBEM2023.COB2023-2435
Abstract
Nuclear fusion is regarded as a clean and safe solution to the growing global energy demand. The most promising device for achieving fusion energy is the tokamak, which confines a plasma using magnetic fields. However, turbulence dominates the radial transport at the edge region of tokamak plasmas, reducing magnetic confinement in fusion experiments, and its control remains a challenge in physics and engineering. The spectral entropy is a useful tool from information theory that can characterize the degree of order/disorder of turbulent fluids and plasmas. We analyze numerical simulations of a fluid model of fusion plasmas in tokamaks. By varying a control parameter we construct a bifurcation diagram of a transition from a turbulent regime to a regime dominated by zonal flows, in which turbulence is suppressed. This transition is then characterized by computing the normalized spectral entropy of the turbulent patterns observed in the numerical simulations. Our results show that the turbulent regime displays a higher degree of entropy, the regime dominated by zonal flows is characterized by lower values of entropy, and the transition from the low-to-high confinement occurs abruptly.
Keywords
Fluid turbulence, Plasma, Information Theory, bifurcation, nonlinear dynamics
