# Development of a New Gas Puff Imaging Diagnostic on the HL-2A Tokamak

## TL;DR

This paper presents a newly developed gas puff imaging diagnostic on the HL-2A tokamak, enabling detailed visualization of plasma edge turbulence and blob structures in the scrape-off layer.

## Contribution

The paper introduces a novel GPI diagnostic system on HL-2A, capable of capturing 2D turbulence structures in the plasma edge during tokamak operations.

## Key findings

- Successfully captured blob structures in the scrape-off layer.
- Revealed turbulence structures in poloidal vs. radial planes.
- Demonstrated the diagnostic's capability during the latest campaign.

## Abstract

A new gas puff imaging (GPI) diagnostic has been developed on the HL-2A tokamak to study two-dimensional plasma edge turbulence in poloidal vs. radial plane. During a discharge, neutral helium or deuterium gas is puffed at the edge of the plasma through a rectangular multi-capillary nozzle to generate a gas cloud on the observing plane. Then a specially designed telescope and a high-speed camera are used to observe and photograph the emission from the neutral gas cloud. The brightness and contrast in the 2-D poloidal vs. radial frames reveal the structures and movements of the turbulence. The diagnostic was put into the first experiment during the latest campaign and successfully captured blob structures of different shapes and sizes in scrape-off layer (SOL).

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Source: https://tomesphere.com/paper/1705.07458