Analysis of Energetic Particle Driven Modes and Interchange Modes in LHD Plasma Using the Gyro-Fluid Code FAR3d

J. Varela; K. Nagaoka; S. Ohdachi; K. Y. Watanabe; Y. Takemura; Y. Narushima; T. Tokuzawa; K. Tanaka; K. Ida; Y. Todo; M. Yoshinuma; R. Seki; K. Nagasaki; S. Kobayashi; P. Adulsiriswad; S. Yamamoto; D. A. Spong; L. Garcia; A. Cappa; Y. Ghai; J. Ortiz; W. A. Cooper; X. Du; S. Sharapov; F. L. Waelbroeck; B. Breizman; D. Zarzoso; C. Hidalgo; A. Azegami

doi:10.1007/s10894-025-00527-x

Analysis of Energetic Particle Driven Modes and Interchange Modes in LHD Plasma Using the Gyro-Fluid Code FAR3d

J. Varela
, K. Nagaoka
, S. Ohdachi
, K. Y. Watanabe
, Y. Takemura
, Y. Narushima
, T. Tokuzawa
, K. Tanaka
, K. Ida
, Y. Todo
, M. Yoshinuma
, R. Seki
, K. Nagasaki
, S. Kobayashi
, P. Adulsiriswad
, S. Yamamoto
, D. A. Spong
, L. Garcia
, A. Cappa
, Y. Ghai

J. Ortiz, W. A. Cooper, X. Du, S. Sharapov, F. L. Waelbroeck, B. Breizman, D. Zarzoso, C. Hidalgo, A. Azegami

Fusion Theory and Modeling

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

Abstract

Energetic particles (EP) generated by the neutral beam injectors (NBI) in Large Helical Device (LHD) destabilize Alfvén Eigenmodes (AE) and energetic particle modes (EPM), leading to a reduction of the device performance. In particular, AE/EPM induce EP losses before thermalization that causes a lower plasma heating efficiency and damages to plasma facing components. Pressure gradient driven modes (PGDM) as interchange and ballooning modes also hamper the capability of LHD to confine the thermal plasma, limiting the maximum thermal plasma β of the discharge. The present study summarizes AE/EPM and PGDM characterization and optimization analysis performed in LHD plasma using the gyro-fluid code FAR3d. The linear and saturation phase of AE/EPM and PGDM leading to the destabilization of MHD burst, energetic-ion-driven resistive interchange mode (EIC) burst, internal collapse and saw-tooth like events are discussed. Optimization trends with respect to the NBI operation regime, magnetic field configuration, thermal plasma properties, external actuators and multiple EP populations effects are explored, comparing experiment and simulation data. Improved operation scenarios are identified and confirmed in dedicated experiments thanks to the minimization or avoidance of AE/EPM and PGDM along the discharge.

Original language	English
Article number	57
Journal	Journal of Fusion Energy
Volume	44
Issue number	2
DOIs	https://doi.org/10.1007/s10894-025-00527-x
State	Published - Dec 2025

Funding

This work was supported by the US DOE under grant DE-FG02-04ER54742, Comunidad de Madrid under the project 2019-T1/AMB-13648, U.S. Department of Energy Office Contract DE-AC05-00OR22725 with UT-Battelle LLC and NIFS07KLPH004. "The data supporting the findings of this study are available in the LHD experiment data repository at https://doi.org/10.57451/lhd.analyzed-data

Keywords

AE
EIC
Energetic particles
LHD
MHD
Stellarator

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10.1007/s10894-025-00527-x

Cite this

Varela, J., Nagaoka, K., Ohdachi, S., Watanabe, K. Y., Takemura, Y., Narushima, Y., Tokuzawa, T., Tanaka, K., Ida, K., Todo, Y., Yoshinuma, M., Seki, R., Nagasaki, K., Kobayashi, S., Adulsiriswad, P., Yamamoto, S., Spong, D. A., Garcia, L., Cappa, A., ... Azegami, A. (2025). Analysis of Energetic Particle Driven Modes and Interchange Modes in LHD Plasma Using the Gyro-Fluid Code FAR3d. Journal of Fusion Energy, 44(2), Article 57. https://doi.org/10.1007/s10894-025-00527-x

@article{7731c0043e65498e9340f5e8b2b38ddf,

title = "Analysis of Energetic Particle Driven Modes and Interchange Modes in LHD Plasma Using the Gyro-Fluid Code FAR3d",

abstract = "Energetic particles (EP) generated by the neutral beam injectors (NBI) in Large Helical Device (LHD) destabilize Alfv{\'e}n Eigenmodes (AE) and energetic particle modes (EPM), leading to a reduction of the device performance. In particular, AE/EPM induce EP losses before thermalization that causes a lower plasma heating efficiency and damages to plasma facing components. Pressure gradient driven modes (PGDM) as interchange and ballooning modes also hamper the capability of LHD to confine the thermal plasma, limiting the maximum thermal plasma β of the discharge. The present study summarizes AE/EPM and PGDM characterization and optimization analysis performed in LHD plasma using the gyro-fluid code FAR3d. The linear and saturation phase of AE/EPM and PGDM leading to the destabilization of MHD burst, energetic-ion-driven resistive interchange mode (EIC) burst, internal collapse and saw-tooth like events are discussed. Optimization trends with respect to the NBI operation regime, magnetic field configuration, thermal plasma properties, external actuators and multiple EP populations effects are explored, comparing experiment and simulation data. Improved operation scenarios are identified and confirmed in dedicated experiments thanks to the minimization or avoidance of AE/EPM and PGDM along the discharge.",

keywords = "AE, EIC, Energetic particles, LHD, MHD, Stellarator",

author = "J. Varela and K. Nagaoka and S. Ohdachi and Watanabe, \{K. Y.\} and Y. Takemura and Y. Narushima and T. Tokuzawa and K. Tanaka and K. Ida and Y. Todo and M. Yoshinuma and R. Seki and K. Nagasaki and S. Kobayashi and P. Adulsiriswad and S. Yamamoto and Spong, \{D. A.\} and L. Garcia and A. Cappa and Y. Ghai and J. Ortiz and Cooper, \{W. A.\} and X. Du and S. Sharapov and Waelbroeck, \{F. L.\} and B. Breizman and D. Zarzoso and C. Hidalgo and A. Azegami",

note = "Publisher Copyright: {\textcopyright} The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025.",

year = "2025",

month = dec,

doi = "10.1007/s10894-025-00527-x",

language = "English",

volume = "44",

journal = "Journal of Fusion Energy",

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Varela, J, Nagaoka, K, Ohdachi, S, Watanabe, KY, Takemura, Y, Narushima, Y, Tokuzawa, T, Tanaka, K, Ida, K, Todo, Y, Yoshinuma, M, Seki, R, Nagasaki, K, Kobayashi, S, Adulsiriswad, P, Yamamoto, S, Spong, DA, Garcia, L, Cappa, A, Ghai, Y, Ortiz, J, Cooper, WA, Du, X, Sharapov, S, Waelbroeck, FL, Breizman, B, Zarzoso, D, Hidalgo, C & Azegami, A 2025, 'Analysis of Energetic Particle Driven Modes and Interchange Modes in LHD Plasma Using the Gyro-Fluid Code FAR3d', Journal of Fusion Energy, vol. 44, no. 2, 57. https://doi.org/10.1007/s10894-025-00527-x

TY - JOUR

T1 - Analysis of Energetic Particle Driven Modes and Interchange Modes in LHD Plasma Using the Gyro-Fluid Code FAR3d

AU - Varela, J.

AU - Nagaoka, K.

AU - Ohdachi, S.

AU - Watanabe, K. Y.

AU - Takemura, Y.

AU - Narushima, Y.

AU - Tokuzawa, T.

AU - Tanaka, K.

AU - Ida, K.

AU - Todo, Y.

AU - Yoshinuma, M.

AU - Seki, R.

AU - Nagasaki, K.

AU - Kobayashi, S.

AU - Adulsiriswad, P.

AU - Yamamoto, S.

AU - Spong, D. A.

AU - Garcia, L.

AU - Cappa, A.

AU - Ghai, Y.

AU - Ortiz, J.

AU - Cooper, W. A.

AU - Du, X.

AU - Sharapov, S.

AU - Waelbroeck, F. L.

AU - Breizman, B.

AU - Zarzoso, D.

AU - Hidalgo, C.

AU - Azegami, A.

N1 - Publisher Copyright: © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025.

PY - 2025/12

Y1 - 2025/12

N2 - Energetic particles (EP) generated by the neutral beam injectors (NBI) in Large Helical Device (LHD) destabilize Alfvén Eigenmodes (AE) and energetic particle modes (EPM), leading to a reduction of the device performance. In particular, AE/EPM induce EP losses before thermalization that causes a lower plasma heating efficiency and damages to plasma facing components. Pressure gradient driven modes (PGDM) as interchange and ballooning modes also hamper the capability of LHD to confine the thermal plasma, limiting the maximum thermal plasma β of the discharge. The present study summarizes AE/EPM and PGDM characterization and optimization analysis performed in LHD plasma using the gyro-fluid code FAR3d. The linear and saturation phase of AE/EPM and PGDM leading to the destabilization of MHD burst, energetic-ion-driven resistive interchange mode (EIC) burst, internal collapse and saw-tooth like events are discussed. Optimization trends with respect to the NBI operation regime, magnetic field configuration, thermal plasma properties, external actuators and multiple EP populations effects are explored, comparing experiment and simulation data. Improved operation scenarios are identified and confirmed in dedicated experiments thanks to the minimization or avoidance of AE/EPM and PGDM along the discharge.

AB - Energetic particles (EP) generated by the neutral beam injectors (NBI) in Large Helical Device (LHD) destabilize Alfvén Eigenmodes (AE) and energetic particle modes (EPM), leading to a reduction of the device performance. In particular, AE/EPM induce EP losses before thermalization that causes a lower plasma heating efficiency and damages to plasma facing components. Pressure gradient driven modes (PGDM) as interchange and ballooning modes also hamper the capability of LHD to confine the thermal plasma, limiting the maximum thermal plasma β of the discharge. The present study summarizes AE/EPM and PGDM characterization and optimization analysis performed in LHD plasma using the gyro-fluid code FAR3d. The linear and saturation phase of AE/EPM and PGDM leading to the destabilization of MHD burst, energetic-ion-driven resistive interchange mode (EIC) burst, internal collapse and saw-tooth like events are discussed. Optimization trends with respect to the NBI operation regime, magnetic field configuration, thermal plasma properties, external actuators and multiple EP populations effects are explored, comparing experiment and simulation data. Improved operation scenarios are identified and confirmed in dedicated experiments thanks to the minimization or avoidance of AE/EPM and PGDM along the discharge.

KW - AE

KW - EIC

KW - Energetic particles

KW - LHD

KW - MHD

KW - Stellarator

UR - https://www.scopus.com/pages/publications/105022662442

U2 - 10.1007/s10894-025-00527-x

DO - 10.1007/s10894-025-00527-x

M3 - Article

AN - SCOPUS:105022662442

SN - 0164-0313

VL - 44

JO - Journal of Fusion Energy

JF - Journal of Fusion Energy

IS - 2

M1 - 57

ER -

Analysis of Energetic Particle Driven Modes and Interchange Modes in LHD Plasma Using the Gyro-Fluid Code FAR3d

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Keywords

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