Rotation Breaking Induced by ELMs on EAST

H. Xiong, G. Xu, Y. Sun, B. Wan, Volker Naulin, Ning Yan, F. Wang

Research output: Contribution to conferencePosterResearchpeer-review

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Abstract

Spontaneous rotation has been observed in LHCD H-mode plasmas with type III ELMs (edge localized modes) on EAST, and it revealed that type III ELMs can induce the loss of both core and edge toroidal rotation. Here we work on the breaking mechanism during the ELMs. Several large tokamaks have discovered ELMs' filamentary structures. It revealed that the ELMs are filamentary perturbations of positive density formed along the local field lines close to the LCFS. Currents flowing in the filaments induce magnetic perturbations, which break symmetry of magnetic field strength and lead to deformation of magnetic surface, thus generate NTV (neoclassical toroidal viscosity) torque that affects toroidal rotation. We adopt 1cm maximum edge magnetic surface displacement from experimental observation, and our calculation shows that the edge torque is about 0.35 N/m2, and the core very small. The expected angular momentum density change is about 3.8 N/m2, nearly 10 times larger than the calculation. Previous work on EAST has suggested that there is a mechanism at the edge that breaks the rotation, while the core rotation change is mostly likely related with momentum transport to the edge. In other words, NTV torque should have less impact on the core but great on edge, which corresponds with the calculation as well. In our calculation, we found that the core has little dependence on the magnetic surface displacement, while the edge relies on it heavily. The exact profile of the edge torque has uncertain that comes from the exact edge displacement profile and the accurate mode number. However, the magnitude of the edge NTV torque is still nearly 0:1 1 N/m2, indicating it should been emphasized while considering rotation change. Further work including transport code is planned.
Original languageEnglish
Publication date2012
Number of pages1
Publication statusPublished - 2012
Event24th IAEA Fusion Energy Conference - San Diego, CA, United States
Duration: 8 Oct 201213 Oct 2012

Conference

Conference24th IAEA Fusion Energy Conference
CountryUnited States
CitySan Diego, CA
Period08/10/201213/10/2012

Cite this

Xiong, H., Xu, G., Sun, Y., Wan, B., Naulin, V., Yan, N., & Wang, F. (2012). Rotation Breaking Induced by ELMs on EAST. Poster session presented at 24th IAEA Fusion Energy Conference, San Diego, CA, United States.
Xiong, H. ; Xu, G. ; Sun, Y. ; Wan, B. ; Naulin, Volker ; Yan, Ning ; Wang, F. / Rotation Breaking Induced by ELMs on EAST. Poster session presented at 24th IAEA Fusion Energy Conference, San Diego, CA, United States.1 p.
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title = "Rotation Breaking Induced by ELMs on EAST",
abstract = "Spontaneous rotation has been observed in LHCD H-mode plasmas with type III ELMs (edge localized modes) on EAST, and it revealed that type III ELMs can induce the loss of both core and edge toroidal rotation. Here we work on the breaking mechanism during the ELMs. Several large tokamaks have discovered ELMs' filamentary structures. It revealed that the ELMs are filamentary perturbations of positive density formed along the local field lines close to the LCFS. Currents flowing in the filaments induce magnetic perturbations, which break symmetry of magnetic field strength and lead to deformation of magnetic surface, thus generate NTV (neoclassical toroidal viscosity) torque that affects toroidal rotation. We adopt 1cm maximum edge magnetic surface displacement from experimental observation, and our calculation shows that the edge torque is about 0.35 N/m2, and the core very small. The expected angular momentum density change is about 3.8 N/m2, nearly 10 times larger than the calculation. Previous work on EAST has suggested that there is a mechanism at the edge that breaks the rotation, while the core rotation change is mostly likely related with momentum transport to the edge. In other words, NTV torque should have less impact on the core but great on edge, which corresponds with the calculation as well. In our calculation, we found that the core has little dependence on the magnetic surface displacement, while the edge relies on it heavily. The exact profile of the edge torque has uncertain that comes from the exact edge displacement profile and the accurate mode number. However, the magnitude of the edge NTV torque is still nearly 0:1 1 N/m2, indicating it should been emphasized while considering rotation change. Further work including transport code is planned.",
author = "H. Xiong and G. Xu and Y. Sun and B. Wan and Volker Naulin and Ning Yan and F. Wang",
year = "2012",
language = "English",
note = "24th IAEA Fusion Energy Conference ; Conference date: 08-10-2012 Through 13-10-2012",

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Xiong, H, Xu, G, Sun, Y, Wan, B, Naulin, V, Yan, N & Wang, F 2012, 'Rotation Breaking Induced by ELMs on EAST' 24th IAEA Fusion Energy Conference, San Diego, CA, United States, 08/10/2012 - 13/10/2012, .

Rotation Breaking Induced by ELMs on EAST. / Xiong, H.; Xu, G.; Sun, Y.; Wan, B.; Naulin, Volker; Yan, Ning; Wang, F.

2012. Poster session presented at 24th IAEA Fusion Energy Conference, San Diego, CA, United States.

Research output: Contribution to conferencePosterResearchpeer-review

TY - CONF

T1 - Rotation Breaking Induced by ELMs on EAST

AU - Xiong, H.

AU - Xu, G.

AU - Sun, Y.

AU - Wan, B.

AU - Naulin, Volker

AU - Yan, Ning

AU - Wang, F.

PY - 2012

Y1 - 2012

N2 - Spontaneous rotation has been observed in LHCD H-mode plasmas with type III ELMs (edge localized modes) on EAST, and it revealed that type III ELMs can induce the loss of both core and edge toroidal rotation. Here we work on the breaking mechanism during the ELMs. Several large tokamaks have discovered ELMs' filamentary structures. It revealed that the ELMs are filamentary perturbations of positive density formed along the local field lines close to the LCFS. Currents flowing in the filaments induce magnetic perturbations, which break symmetry of magnetic field strength and lead to deformation of magnetic surface, thus generate NTV (neoclassical toroidal viscosity) torque that affects toroidal rotation. We adopt 1cm maximum edge magnetic surface displacement from experimental observation, and our calculation shows that the edge torque is about 0.35 N/m2, and the core very small. The expected angular momentum density change is about 3.8 N/m2, nearly 10 times larger than the calculation. Previous work on EAST has suggested that there is a mechanism at the edge that breaks the rotation, while the core rotation change is mostly likely related with momentum transport to the edge. In other words, NTV torque should have less impact on the core but great on edge, which corresponds with the calculation as well. In our calculation, we found that the core has little dependence on the magnetic surface displacement, while the edge relies on it heavily. The exact profile of the edge torque has uncertain that comes from the exact edge displacement profile and the accurate mode number. However, the magnitude of the edge NTV torque is still nearly 0:1 1 N/m2, indicating it should been emphasized while considering rotation change. Further work including transport code is planned.

AB - Spontaneous rotation has been observed in LHCD H-mode plasmas with type III ELMs (edge localized modes) on EAST, and it revealed that type III ELMs can induce the loss of both core and edge toroidal rotation. Here we work on the breaking mechanism during the ELMs. Several large tokamaks have discovered ELMs' filamentary structures. It revealed that the ELMs are filamentary perturbations of positive density formed along the local field lines close to the LCFS. Currents flowing in the filaments induce magnetic perturbations, which break symmetry of magnetic field strength and lead to deformation of magnetic surface, thus generate NTV (neoclassical toroidal viscosity) torque that affects toroidal rotation. We adopt 1cm maximum edge magnetic surface displacement from experimental observation, and our calculation shows that the edge torque is about 0.35 N/m2, and the core very small. The expected angular momentum density change is about 3.8 N/m2, nearly 10 times larger than the calculation. Previous work on EAST has suggested that there is a mechanism at the edge that breaks the rotation, while the core rotation change is mostly likely related with momentum transport to the edge. In other words, NTV torque should have less impact on the core but great on edge, which corresponds with the calculation as well. In our calculation, we found that the core has little dependence on the magnetic surface displacement, while the edge relies on it heavily. The exact profile of the edge torque has uncertain that comes from the exact edge displacement profile and the accurate mode number. However, the magnitude of the edge NTV torque is still nearly 0:1 1 N/m2, indicating it should been emphasized while considering rotation change. Further work including transport code is planned.

M3 - Poster

ER -

Xiong H, Xu G, Sun Y, Wan B, Naulin V, Yan N et al. Rotation Breaking Induced by ELMs on EAST. 2012. Poster session presented at 24th IAEA Fusion Energy Conference, San Diego, CA, United States.