Theory of the Drift-Wave Instability at Arbitrary Collisionality

Area of Science:

• Plasma Physics
• Computational Physics
• Nuclear Fusion

Background:

• Magnetized plasmas are crucial for nuclear fusion.
• Collisional effects significantly impact plasma behavior and instabilities.
• Current simulation codes may not fully capture Coulomb collision effects.

Purpose of the Study:

• Introduce a numerically efficient framework for Coulomb collisions at arbitrary collisionalities.
• Investigate the impact of collisions on magnetized plasma instabilities.
• Improve the accuracy of plasma turbulence simulations.

Main Methods:

• Expanded the distribution function on a Hermite-Laguerre polynomial basis.
• Developed a model for arbitrary mean-free path collisions.
• Focused on drift-wave instability analysis.

Main Results:

• Successfully retrieved established collisional and collisionless limits.
• Demonstrated deviations from current state-of-the-art collision operators.
• Highlighted the necessity of the full Coulomb operator for accurate growth rates and eigenmode spectra.

Conclusions:

• The proposed spectral method offers superior efficiency over finite difference methods.
• Accurate modeling of Coulomb collisions is essential for predicting transport in fusion devices.
• This framework advances the simulation of magnetized plasmas for fusion energy applications.