Implementation of magnetic compressional effects at arbitrary wavelength in the global version of GENE

• Published in: Computer physics communications 2025-02, Vol.307 (C), p.109410, Article 109410
• Main Authors: Wilms, Felix, Merlo, Gabriele, Sheffield, Facundo, Görler, Tobias, Bañón Navarro, Alejandro, Jenko, Frank
• Format: Article
• Language: English
• Subjects: Electromagnetic simulation; Gyrokinetic simulation; Magnetic compression
• ISSN: 0010-4655
• DOI: 10.1016/j.cpc.2024.109410

The global tokamak code GENE has been extended including the effect of magnetic compression caused by B1,|| turbulent fluctuations of the magnetic field parallel to the equilibrium one. This paper outlines the basic structure of the algorithm, valid at arbitrary wavelengths of the gyrokinetic fluctuations, with emphasis on the numerical construction of the so-called “gyrodisk-integral” operators necessary for the model. The numerical implementation is successfully verified against radially local simulations, recovering excellent agreement. Global tokamak simulations are presented as well. The upgrade enables studying a large variety of new physical scenarios at high plasma-β, such as kinetic ballooning modes, MHD-like modes or the interaction of B1,|| with fast particle modes, reducing the gap between gyrokinetic models and physically realistic systems. •The global gyrokinetic code GENE was upgraded to include parallel magnetic field perturbations B1,|| at arbitrary wavelengths.•The approach uses a real-space representation in the radial direction and can readily be applied to other global codes.•The construction of the necessary operators adds minimal cost, requiring only minor changes to GENE's existing algorithm.