Transition to collisionless ion-temperature-gradient-driven plasma turbulence: a dynamical systems approach

Area of Science:

• Plasma Physics
• Dynamical Systems Theory
• Turbulence Studies

Background:

• Ion-temperature-gradient (ITG) driven turbulence is a key process in plasma physics.
• Understanding the transition to collisionless ITG turbulence is crucial for fusion energy research.
• Zonal flows are known to influence plasma turbulence, but their precise role in threshold dynamics requires further investigation.

Purpose of the Study:

• To investigate the transition to collisionless ion-temperature-gradient-driven plasma turbulence.
• To apply dynamical systems theory to a simplified model of plasma turbulence.
• To determine the impact of zonal flows on the turbulence threshold and quantify the
• Main_Methods: [
• Development of a 10 degrees of freedom dynamical system model for plasma turbulence.
• Analysis of a four-dimensional center manifold within the model.
• Application of dynamical systems theory to predict and analyze turbulence transitions.

Main Methods:

• Dynamical systems theory applied to a 10 degrees of freedom plasma model.
• Analysis of a four-dimensional center manifold to understand turbulence dynamics.
• Prediction and quantification of the threshold shift for turbulence onset.

Main Results:

• The study predicts a
• Dimits shift
• in the turbulence threshold.
• The excitation of zonal flows is identified as the cause of this shift.
• The exact value of the Dimits shift is established for the considered model.

Conclusions:

• Dynamical systems theory provides a powerful framework for understanding plasma turbulence.
• Zonal flows play a critical role in modifying the onset threshold of collisionless ITG turbulence.
• The findings contribute to a more precise understanding of turbulence regulation mechanisms in plasmas.