# First principles gyrokinetic analysis of electromagnetic plasma instabilities

## TL;DR

This paper presents a gyrokinetic theoretical framework and numerical analysis of electromagnetic plasma instabilities in tokamaks, including energy conservation and destabilizing mechanisms, using the Orb5 code.

## Contribution

It provides a first-principles derivation of the gyrokinetic model, energy conservation diagnostics, and analysis of instability mechanisms in electromagnetic tokamak plasmas.

## Key findings

- Energy conservation verified via Noether theorem in Orb5
- Analysis of destabilizing mechanisms for ITG and electrostatic instabilities
- Transition to Kinetic Ballooning Modes at high electromagnetic beta

## Abstract

A two-fold analysis of electromagnetic core tokamak instabilities in the framework of the gyrokinetic theory is presented. First principle theoretical foundations of the gyrokinetic theory are used to explain and justify the numerical results obtained with the global electromagnetic particle-in-cell code Orb5 whose model is derived from the Lagrangian formalism. The energy conservation law corresponding to the Orb5 model is derived from the Noether theorem and implemented in the code as a diagnostics for energy balance and conservation verification. An additional Noether theorem based diagnostics is implemented in order to analyse destabilising mechanisms for the electrostatic and the electromagnetic Ion Temperature Gradient (ITG) instabilities in the core region of the tokamak. The transition towards the Kinetic Ballooning Modes (KBM) at high electromagnetic $\beta$ is also investigated.