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Main Authors: Zheng, Linjin, Kotschenreuther, M. T., Waelbroeck, F. L., Austin, M. E., Rowan, W. L., Valanju, P., Liu, X.
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2401.15488
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_version_ 1866910309975851008
author Zheng, Linjin
Kotschenreuther, M. T.
Waelbroeck, F. L.
Austin, M. E.
Rowan, W. L.
Valanju, P.
Liu, X.
author_facet Zheng, Linjin
Kotschenreuther, M. T.
Waelbroeck, F. L.
Austin, M. E.
Rowan, W. L.
Valanju, P.
Liu, X.
contents The steady-state confinement, beta limit, and divertor heat load are among the most concerned issues for toroidal confinement of fusion plasmas. In this work, we show that the negative triangularity tokamak has promising prospects to address these issues. We first demonstrate that the negative triangularity tokamak generates the filed line rotation transform more effectively. This brings bright prospects for the advanced steady-state tokamak scenario. Given this, the stability and confinement features of negative triangularity tokamak are investigated. We point out that the negative triangularity configuration with a broad pressure profile is indeed more unstable for low-n magnetohydrodynamic modes than the positive triangularity case so that the H-mode confinement can hardly be achieved in this configuration, where n is the toroidal mode number. Nevertheless, we found that the negative triangularity configuration with high bootstrap current fraction, high poloidal beta, and peaked pressure profiles can achieve higher normalized beta for low-n modes than the positive triangularity case. In a certain parameter domain, the normalized beta can reach about twice the extended Troyon limit, while the same computation indicates that the positive triangularity configuration is indeed constrained by the Troyon limit. This shows that the negative triangularity tokamaks are not only favorable for divertor design to avoid the edge localized modes but also can have promising prospects for advanced steady-state confinement of fusion plasmas in high beta.
format Preprint
id arxiv_https___arxiv_org_abs_2401_15488
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Prospects of negative triangularity tokamak for advanced steady-state confinement of fusion plasmas
Zheng, Linjin
Kotschenreuther, M. T.
Waelbroeck, F. L.
Austin, M. E.
Rowan, W. L.
Valanju, P.
Liu, X.
Plasma Physics
The steady-state confinement, beta limit, and divertor heat load are among the most concerned issues for toroidal confinement of fusion plasmas. In this work, we show that the negative triangularity tokamak has promising prospects to address these issues. We first demonstrate that the negative triangularity tokamak generates the filed line rotation transform more effectively. This brings bright prospects for the advanced steady-state tokamak scenario. Given this, the stability and confinement features of negative triangularity tokamak are investigated. We point out that the negative triangularity configuration with a broad pressure profile is indeed more unstable for low-n magnetohydrodynamic modes than the positive triangularity case so that the H-mode confinement can hardly be achieved in this configuration, where n is the toroidal mode number. Nevertheless, we found that the negative triangularity configuration with high bootstrap current fraction, high poloidal beta, and peaked pressure profiles can achieve higher normalized beta for low-n modes than the positive triangularity case. In a certain parameter domain, the normalized beta can reach about twice the extended Troyon limit, while the same computation indicates that the positive triangularity configuration is indeed constrained by the Troyon limit. This shows that the negative triangularity tokamaks are not only favorable for divertor design to avoid the edge localized modes but also can have promising prospects for advanced steady-state confinement of fusion plasmas in high beta.
title Prospects of negative triangularity tokamak for advanced steady-state confinement of fusion plasmas
topic Plasma Physics
url https://arxiv.org/abs/2401.15488