Transient grating spectroscopy of thermal diffusivity degradation in deuterium implanted tungsten

TL;DR

This study uses transient grating spectroscopy to analyze how deuterium plasma exposure degrades the thermal diffusivity of tungsten, revealing surface blister formation and the dominant role of ion flux density in degradation.

Contribution

It provides the first detailed measurement of thermal diffusivity degradation in tungsten due to deuterium plasma exposure using transient grating spectroscopy.

Findings

Thermal diffusivity decreases significantly with plasma exposure.

Surface blisters form with similar morphology across fluences.

Ion flux density influences degradation more than fluence.

Abstract

Using transient grating spectroscopy, we measure thermal diffusivity and surface acoustic wave speed in tungsten exposed to different fluences of deuterium plasma. Scanning electron microscopy (SEM) shows the formation of surface blisters that have similar morphology for all fluences. A significant reduction in thermal diffusivity and surface acoustic wave speed occurs as a result of plasma exposure. A saturation of the thermal diffusivity reduction with fluence is seen. Deuterium ion flux density appears play a more important role in the thermal diffusivity reduction than the fluence. These results have important implications for plasma facing components in future fusion reactors.