Impurity seeding for suppression of the near Scrape-Off Layer heat flux feature in tokamak limited plasmas

TL;DR

This paper investigates impurity seeding as a method to mitigate the steep heat flux in the near Scrape-Off Layer of tokamak plasmas, aiming to reduce thermal loads and improve operational safety in fusion reactors.

Contribution

It introduces a novel impurity seeding technique for near SOL heat flux suppression, supported by experimental results from the TCV tokamak.

Findings

Successful reduction of near SOL heat flux in experiments

Impurity seeding effectively mitigates thermal loads

Potential for improved tokamak operational safety

Abstract

In inboard-limited plasmas, foreseen to be used in future fusion reactors start-up and ramp down phases, the Scrape-Off Layer (SOL) exhibits two regions: the "near" and "far" SOL. The steep radial gradient of the parallel heat flux associated with the near SOL can result in excessive thermal loads onto the solid surfaces, damaging them and/or limiting the operational space of a fusion reactor. In this article, leveraging the results presented in [F. Nespoli et al., Nuclear Fusion 2017], we propose a technique for the mitigation and suppression of the near SOL heat flux feature by impurity seeding. First successful experimental results from the TCV tokamak are presented and discussed.