Experimental investigations and modeling of low-temperature plasma reactor for simulating parasitic discharges such as those expected under Tokamak divertor dome

摘要

A low temperature plasma reactor has been developed to simulate some of the plasma/surface processes that can occur under the divertor and in the far scrape-off layer regions of tokamaks. This CASIMIR (Chemical Ablation, Sputtering, Ionization, Multi-wall Interaction and Redeposition) device is envisioned as an ITER divertor dome simulator. The goal is to address issues related to the chemistry of hydrocarbon erosion products, along with transport, transformation, and redeposition of these products in parasitic plasma environments. We will first describe the apparatus, as well as the plasma diagnostics implemented on the reactor. We will then show, by means of optical emission spectroscopy, electrical probe, mass-spectrometry measurements, and PIC modeling that the CASIMIR device is able to generate plasma flow in accordance with the plasma characteristics simulated for parasitic discharges under the divertor.