Title: Analysing the effects of heating and gas puffing in Proto-MPEX helicon and auxiliary heated plasmas

Abstract

The Material Plasma Exposure Experiment (MPEX) is being constructed at Oak Ridge National Laboratory to investigate critical fusion reactor issues, such as plasma–material interactions (PMIs) under reactor-relevant conditions and time scales. The linear device Proto-MPEX was used as a test bed to address anticipated research and development issues associated with heating scenarios and establish the physics basis for MPEX. The SOLPS-ITER code suite has been applied to understand plasma and neutral transport in Proto-MPEX and to increase confidence in predictive simulations for MPEX. Coupling between COMSOL and SOLPS is performed to implement a 2D electron heating profile of the helicon source. The simulations show reasonable agreement with the experimental data for plasma with helicon and auxiliary electron cyclotron heating (ECH). Both Bohm and constant diffusion (D$$_\perp$$: 0.5 m² s^–1 and $$\chi_\perp$$: 1 m² s^–1) simulations show similar levels of agreement with respect to the sparse experimental data available, assuming a few per cent impurity concentration. ECH significantly increases the target electron temperature, however, the target electron density is reduced compared to helicon-only heated plasmas due to an increase in flow velocity and radial losses. The simulations show that further increasing the ECH power results in an increase in the target electron density due to increased recycling flux and ionization. The results indicate that ECH significantly enhances the target heat flux, with ECH power of 50 kW increasing the target heat flux from 0.4 to 17 MW m^–2. It is found that a small amount of gas puffing (GP) near the target plate can further increase the target heat fluxes at the higher ECH power cases, but the target heat flux is reduced at higher GP conditions due to a significant reduction in electron temperature via radiation. ECH and GP scenarios can generate a higher target flux, facilitating improved PMI studies with more reactor-relevant plasma conditions.

Authors:

Islam, Md Shahinul  ^[1];

• Search DOE PAGES for author "Islam, Md Shahinul"
• Search DOE PAGES for ORCID "0000-0003-2019-4001"

Lore, Jeremy D.  ^[1];

• Search DOE PAGES for author "Lore, Jeremy D."
• Search DOE PAGES for ORCID "0000-0002-9192-465X"

Lau, Cornwall  ^[1];

• Search DOE PAGES for author "Lau, Cornwall"
• Search DOE PAGES for ORCID "0000-0002-8576-5867"

Rapp, Juergen  ^[1]

• Search DOE PAGES for author "Rapp, Juergen"
• Search DOE PAGES for ORCID "0000-0003-2785-9280"

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+ Show Author Affiliations

1. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Publication Date:

Tue Aug 08 00:00:00 EDT 2023

Research Org.:

Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1994699

Grant/Contract Number:  

AC05-00OR22725

Resource Type:

Accepted Manuscript

Journal Name:

Plasma Physics and Controlled Fusion

Additional Journal Information:

Journal Volume: 65; Journal Issue: 9; Journal ID: ISSN 0741-3335

Publisher:

IOP Science

Country of Publication:

United States

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY; SOLPS-ITER; MPEX; plasma transport; plasma heating and fueling; divertor