Turbulence phase space in simple magnetized toroidal plasmas.

Area of Science:

• Plasma physics
• Magnetohydrodynamics
• Fluid dynamics

Background:

• Understanding plasma turbulence is crucial for magnetic confinement fusion.
• Simple magnetized tori (SMT) offer a simplified model for studying plasma behavior.
• Previous research has explored various aspects of plasma turbulence, but 3D global simulations in SMTs are novel.

Purpose of the Study:

• To explore plasma turbulence in a simple magnetized torus (SMT) using 3D global fluid simulations.
• To identify and characterize different turbulence regimes within the SMT.
• To investigate the transitions between these regimes under varying conditions.

Main Methods:

• Three-dimensional global fluid simulations were employed.
• The simulations modeled plasma behavior within a simple magnetized torus geometry.
• Parameter variations, specifically the pitch of field lines, were used to induce transitions between regimes.

Main Results:

• Three distinct plasma turbulence regimes were identified: ideal interchange, resistive interchange, and drift-wave.
• A novel resistive interchange mode regime was discovered.
• Simulations showed a transition from ideal to resistive interchange modes as the field line pitch decreased.
• The drift-wave regime was found to be accessible primarily at very low collisionalities.

Conclusions:

• The study successfully characterized three turbulence regimes in SMTs, including a newly identified resistive interchange mode.
• The findings provide insights into the complex dynamics of magnetized plasma turbulence.
• The accessibility of the drift-wave regime highlights the importance of collisionality in experimental conditions.