# Dynamics of plasma reconfiguration after pellet injection in Heliotron J

## TL;DR

This paper studies how plasma in a fusion device reconfigures after a pellet injection, showing improved confinement and changes in magnetic field structure.

## Contribution

The study reveals non-adiabatic plasma reconfiguration and improved confinement following pellet injection in Heliotron J.

## Key findings

- Plasma achieves improved confinement during reconfiguration after pellet injection.
- Plasma shrinking and expansion occur during the reconfiguration process.
- Magnetic field line structure in the divertor region changes during reconfiguration.

## Abstract

Because of the many degrees of freedom in magnetized plasmas, the plasma is largely reconfigured when the plasma achieves a non-equilibrium steady state in response to changes in the internal environment. Here we report observations of a plasma reconfiguration process when the density is increased by pellet injection in Heliotron J. The plasma shows no adiabatic response to pellet injection and achieves an improved confinement during the reconfiguration process. It was found that plasma shrinking and expansion arose and the magnetic field line structure in the divertor region also changed in the plasma reconfiguration process.