ETG Turbulence Induced Energy flux in the Large Laboratory Plasma

TL;DR

This study demonstrates the excitation of ETG-driven turbulence in a laboratory plasma device, measuring correlated fluctuations and resulting heat flux, and compares experimental results with theoretical models.

Contribution

First experimental demonstration of ETG turbulence and associated heat flux in a large laboratory plasma device with detailed fluctuation measurements.

Findings

ETG turbulence was successfully excited under finite plasma beta conditions.

Strong negative correlations between density, temperature, and potential fluctuations were observed.

The measured heat flux is outward and aligns with theoretical ETG heat flux estimates.

Abstract

The Large Volume Plasma Device (LVPD) has successfully demonstrated excitation of Electron Temperature Gradient (ETG) driven turbulence in finite plasma beta condition , where the threshold condition for ETG turbulence is satisfied. The observed mode follows wave-vector scaling and frequency ordering of ETG turbulence. Simultaneous measurement of fluctuations in electron temperature, $\delta T_e $, plasma density, $\delta n_e $ and potential,$\delta V_f $ are obtained. Strong negative correlation with correlation coefficients $ C_{\delta n_e \delta \phi_f}\sim -0.8 $ and $ C_{\delta T_e \delta \phi }\sim -0.9 $ are observed between density and potential and temperature and potential fluctuations, respectively. These correlated density, temperature and potential fluctuations lead to generation of turbulent heat flux. The measured heat flux is compared with theoretically estimated heat flux from ETG model equations. The experimental result shows that net heat flux is directed radially outward.