The Information Length Concept Applied to Plasma Turbulence

Area of Science:

• Plasma Physics
• Statistical Mechanics
• Computational Physics

Background:

• Anomalous transport in fusion plasma is crucial for reactor performance.
• Understanding turbulent transport mechanisms, like avalanches, is key.
• Existing methods may not fully capture the complexity of these processes.

Purpose of the Study:

• To develop and apply a novel statistical methodology for studying anomalous transport in fusion plasma.
• To analyze heat flux time traces from gyrokinetic simulations.
• To investigate the differences between flux-driven and gradient-driven plasma turbulence.

Main Methods:

• Utilizing three time traces from the full-f gyrokinetic code GKNET.
• Applying statistical methods to analyze heat flux as a function of radial position.
• Employing the information length concept with Boltzmann-Gibbs and Tsallis entropy.

Main Results:

• Simulation data show transport with medium and long radial correlation lengths, including avalanche phenomena.
• Dynamical states in flux-driven and gradient-driven configurations appear similar.
• Tsallis entropy analysis reveals significant differences in probability distribution functions between the two configurations.

Conclusions:

• The applied statistical methodology provides new insights into anomalous transport.
• While overall dynamics may seem similar, higher moments of probability distributions differ notably between driven and decaying turbulence.
• Tsallis entropy is effective in distinguishing subtle differences in plasma turbulent states.