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Title: Validating the simulation of beam-ion charge exchange in MAST Upgrade

Abstract

Abstract Simulation of the impact of charge-exchange (CX) reactions on beam ions in the Mega Amp Spherical Tokamak (MAST) Upgrade was compared to measurements carried out with a fission chamber (neutron fluxes) and a fast ion deuterium-alpha (FIDA) diagnostic. A simple model was developed to reconstruct the outer-midplane neutral density based on measurements of deuterium-alpha emission from edge neutrals, and on Thomson scattering measurements of electron density and temperature. The main computational tools used were the ASCOT orbit-following code and the FIDASIM code for producing synthetic FIDA signals. The neutral density reconstruction agrees qualitatively with SOLPS-ITER modelling and yields a synthetic passive FIDA signal that is consistent with measurement. When CX losses of beam ions are accounted for, predicted neutron emission rates are quantitatively more consistent with measurement. It was necessary to account for CX losses of beam ions in simulations to reproduce the measured passive FIDA signal quantitatively and qualitatively. The results suggest that the neutral density reconstruction is a good approximation, that CX with edge neutrals causes significant beam-ion losses in MAST Upgrade, typically 20% of beam power, and that the ASCOT fast-ion CX model can be used to accurately predict the redistribution and loss of beam ionsmore » due to CX.« less

Authors:
ORCiD logo; ; ORCiD logo; ; ; ORCiD logo; ORCiD logo; ; ORCiD logo; ; ORCiD logo; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
2263515
Alternate Identifier(s):
OSTI ID: 2229964
Grant/Contract Number:  
SC0019007
Resource Type:
Published Article
Journal Name:
Plasma Physics and Controlled Fusion
Additional Journal Information:
Journal Name: Plasma Physics and Controlled Fusion Journal Volume: 66 Journal Issue: 2; Journal ID: ISSN 0741-3335
Publisher:
IOP Publishing
Country of Publication:
United Kingdom
Language:
English

Citation Formats

Ollus, P., Allan, S., Harrison, J. R., Jackson, A. R., Kurki-Suonio, T., McClements, K. G., Michael, C. A., Moulton, D., Patel, B. S., Robson, M., Snicker, A., Varje, J., Vincent, C., and the MAST-U Team. Validating the simulation of beam-ion charge exchange in MAST Upgrade. United Kingdom: N. p., 2023. Web. doi:10.1088/1361-6587/ad15ed.
Ollus, P., Allan, S., Harrison, J. R., Jackson, A. R., Kurki-Suonio, T., McClements, K. G., Michael, C. A., Moulton, D., Patel, B. S., Robson, M., Snicker, A., Varje, J., Vincent, C., & the MAST-U Team. Validating the simulation of beam-ion charge exchange in MAST Upgrade. United Kingdom. https://doi.org/10.1088/1361-6587/ad15ed
Ollus, P., Allan, S., Harrison, J. R., Jackson, A. R., Kurki-Suonio, T., McClements, K. G., Michael, C. A., Moulton, D., Patel, B. S., Robson, M., Snicker, A., Varje, J., Vincent, C., and the MAST-U Team. Thu . "Validating the simulation of beam-ion charge exchange in MAST Upgrade". United Kingdom. https://doi.org/10.1088/1361-6587/ad15ed.
@article{osti_2263515,
title = {Validating the simulation of beam-ion charge exchange in MAST Upgrade},
author = {Ollus, P. and Allan, S. and Harrison, J. R. and Jackson, A. R. and Kurki-Suonio, T. and McClements, K. G. and Michael, C. A. and Moulton, D. and Patel, B. S. and Robson, M. and Snicker, A. and Varje, J. and Vincent, C. and the MAST-U Team},
abstractNote = {Abstract Simulation of the impact of charge-exchange (CX) reactions on beam ions in the Mega Amp Spherical Tokamak (MAST) Upgrade was compared to measurements carried out with a fission chamber (neutron fluxes) and a fast ion deuterium-alpha (FIDA) diagnostic. A simple model was developed to reconstruct the outer-midplane neutral density based on measurements of deuterium-alpha emission from edge neutrals, and on Thomson scattering measurements of electron density and temperature. The main computational tools used were the ASCOT orbit-following code and the FIDASIM code for producing synthetic FIDA signals. The neutral density reconstruction agrees qualitatively with SOLPS-ITER modelling and yields a synthetic passive FIDA signal that is consistent with measurement. When CX losses of beam ions are accounted for, predicted neutron emission rates are quantitatively more consistent with measurement. It was necessary to account for CX losses of beam ions in simulations to reproduce the measured passive FIDA signal quantitatively and qualitatively. The results suggest that the neutral density reconstruction is a good approximation, that CX with edge neutrals causes significant beam-ion losses in MAST Upgrade, typically 20% of beam power, and that the ASCOT fast-ion CX model can be used to accurately predict the redistribution and loss of beam ions due to CX.},
doi = {10.1088/1361-6587/ad15ed},
journal = {Plasma Physics and Controlled Fusion},
number = 2,
volume = 66,
place = {United Kingdom},
year = {Thu Dec 28 00:00:00 EST 2023},
month = {Thu Dec 28 00:00:00 EST 2023}
}

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https://doi.org/10.1088/1361-6587/ad15ed

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