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

M. S. Islam; J. D. Lore; C. Lau; J. Rapp

doi:10.1088/1361-6587/ace793

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

M. S. Islam, J. D. Lore, C. Lau, J. Rapp

Research output: Contribution to journal › Article › peer-review

4 Scopus citations

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 ⊥ : 0.5 m² s⁻¹ and χ ⊥ : 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.

Original language	English
Article number	095020
Journal	Plasma Physics and Controlled Fusion
Volume	65
Issue number	9
DOIs	https://doi.org/10.1088/1361-6587/ace793
State	Published - Sep 2023

Funding

The authors would like to thank Dr Ezekial Unterberg, Dr Lauren Nuckols, Dr Atul Kumar, Dr Jae-Sun Park, Dr Curtis Johnson, Dr Sebastian De Pascuale, Dr Mark Cianciosa, Dr Iván Paradela Pérez, ORNL for their valuable suggestions and comments. The authors also want to thank Dr Jorge Gonzalez, DIFFER and Dr Elena Tonello, Politecnico di Milano for their help with the SOLPS simulation setup for a linear fusion device geometry. This manuscript has been authored by UT-Battelle, LLC, under Contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The publisher acknowledges the US government license to provide public access under the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The publisher acknowledges the US government license to provide public access under the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ).

Funders	Funder number
DOE Public Access Plan
U.S. Department of Energy
Oak Ridge National Laboratory
Politecnico di Milano	DE-AC05-00OR22725

Keywords

MPEX
SOLPS-ITER
divertor
plasma heating and fuelling
plasma transport

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1088/1361-6587/ace793

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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 ⊥ : 0.5 m2 s−1 and χ ⊥ : 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.",

keywords = "MPEX, SOLPS-ITER, divertor, plasma heating and fuelling, plasma transport",

author = "Islam, {M. S.} and Lore, {J. D.} and C. Lau and J. Rapp",

note = "Publisher Copyright: {\textcopyright} 2023 The Author(s). Published by IOP Publishing Ltd",

year = "2023",

month = sep,

doi = "10.1088/1361-6587/ace793",

language = "English",

volume = "65",

journal = "Plasma Physics and Controlled Fusion",

issn = "0741-3335",

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T1 - Analysing the effects of heating and gas puffing in Proto-MPEX helicon and auxiliary heated plasmas

AU - Islam, M. S.

AU - Lore, J. D.

AU - Lau, C.

AU - Rapp, J.

PY - 2023/9

Y1 - 2023/9

N2 - 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 ⊥ : 0.5 m2 s−1 and χ ⊥ : 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.

AB - 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 ⊥ : 0.5 m2 s−1 and χ ⊥ : 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.

KW - MPEX

KW - SOLPS-ITER

KW - divertor

KW - plasma heating and fuelling

KW - plasma transport

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U2 - 10.1088/1361-6587/ace793

DO - 10.1088/1361-6587/ace793

M3 - Article

AN - SCOPUS:85167871447

SN - 0741-3335

VL - 65

JO - Plasma Physics and Controlled Fusion

JF - Plasma Physics and Controlled Fusion

IS - 9

M1 - 095020

ER -

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

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Keywords

UN SDGs

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