# Verification of long wavelength electromagnetic modes with a gyrokinetic-fluid hybrid model in the XGC code

## TL;DR

This paper extends the XGC1 gyrokinetic PIC code to include a hybrid model with fluid electrons, enabling verification of long wavelength electromagnetic modes like shear Alfvén and tearing modes in different magnetic geometries.

## Contribution

It introduces a gyrokinetic-fluid hybrid model in XGC1 for electromagnetic mode verification, combining gyrokinetic ions with fluid electrons.

## Key findings

- Successful verification of shear Alfvén waves.
- Verification of resistive tearing modes.
- Application in cylindrical and toroidal geometries.

## Abstract

As an alternative option to kinetic electrons, the gyrokinetic total-f particle-in-cell (PIC) code XGC1 has been extended to the MHD/fluid type electromagnetic regime by combining gyrokinetic PIC ions with massless drift-fluid electrons analogous to Chen and Parker, Physics of Plasmas 8, 441 (2001). Two representative long wavelength modes, shear Alfv\'en waves and resistive tearing modes, are verified in cylindrical and toroidal magnetic field geometries.