The impact of magnetic geometry on wave modes in cylindrical plasmas

TL;DR

This paper explores how different magnetic field geometries in cylindrical plasmas affect wave modes, revealing methods to control drift waves, enhance wave-driven plasma production, and create gap eigenmodes for fusion research.

Contribution

It systematically analyzes the effects of uniform, focused, and rippled magnetic geometries on plasma wave modes in cylindrical configurations, providing new insights for plasma control and fusion applications.

Findings

Suppression of drift waves by increasing magnetic field strength.

Enhanced helicon wave production with focused magnetic fields.

Formation of gap eigenmodes via local defects in periodic systems.

Abstract

Both space and laboratory plasmas can be associated with static magnetic field, and the field geometry varies from uniform to non-uniform. This thesis investigates the impact of magnetic geometry on wave modes in cylindrical plasmas. The cylindrical configuration is chosen so as to explore this impact in a tractable but experimentally realisable configuration. Three magnetic geometries are considered: uniform, focused and rippled. These studies suggest suppressing drift waves in a uniformly magnetised plasma by increasing the field strength, enhancing the efficiency of helicon wave production of plasma by using a focused magnetic field, and forming a gap eigenmode on a linear plasma device by introducing a local defect to the system's periodicity, which is useful for understanding the gap-mode formation and interaction with energetic particles in fusion plasmas.