Heat flux deposition pattern on the inner first wall of Tore Supra

TL;DR

This study characterizes the heat flux deposition pattern on Tore Supra's inner first wall, revealing deviations from expected models and the impact of high-power discharges on wall resilience.

Contribution

It provides new diagnostic data on heat flux distribution and damage mechanisms on upgraded CFC first wall elements in Tore Supra.

Findings

Heat flux pattern deviates from cosine law.

Strong perpendicular heat flux influences deposition.

Wall withstands twice the typical power during high-energy shots.

Abstract

The Inner First Wall (IFW) is the main limiter in Tore Supra for long and powerful discharges. The original graphite IFW was partly damaged by 8 years of operation and a sector of 60{\textdegree} was replaced between 1995 and 1997 by CFC brazed elements. They are designed to accept twice as much flux (2 MW/m${}^2$) as the older ones and are expected to be more resilient. The new elements gave the opportunity to install diagnostics (thermocouples and langmuir probes) on a poloidal sector, to characterise the behaviour of the new IFW and especially the heat flux profile. The pattern doesn't follow the cosine law and is governed by strong perpendicular heat flux and abnormal deposition at the contact point between the limiter and the plasma. The most energetic shots of the last campaign showed that the IFW could be loaded with twice the power deposited during these shots.