The role of electron-scale turbulence in the JET tokamak: experiments and modelling

Mantica, P.; Bonanomi, N.; Mariani, A.; Carvalho, P.; Delabie, E.; Garcia, J.; Hawkes, N.; Johnson, T.; Keeling, D.; Sertoli, M.; Staebler, G. M.; Szepesi, G.; Taylor, D.; Thorman, A.

doi:10.1088/1741-4326/ac146e

Title: The role of electron-scale turbulence in the JET tokamak: experiments and modelling

Abstract

Dedicated electron heat transport experiments have been carried out in L- and H-mode Deuterium plasmas of the JET-ILW tokamak to identify the amount of electron heat carried by electron-scale electron temperature gradient (ETG) modes. Ion cyclotron resonance heating at different positions has been used to probe the response of the electron temperature inverse gradient length R/L_Te to changes in electron heat flux qe, while different amounts of neutral beam heating allowed to scan the ratio of ion to electron temperature T_e/T_i, which is a key parameter for the onset of ETGs. Results indicate a steepening of the normalized qe vs R/L_Te curve above R/LT_e ~ 8 for T_e/T_i ≤ 1, suggestive of the ETG onset. Ion-scale gyro-kinetic (GK) simulations match the ion heat flux and the low-R/L_Te part of the qe curve, but do not reproduce such steepening at high R/L_Te. Multi-scale GK simulations covering both ion and electron scales and including one impurity bundling light and heavy species indicate an ETG contribution only for R/L_Te values larger than the experimental ones. Sensitivity studies of such result are difficult to achieve due to limitation in numerical resources. The quasi-linear TGLF model has been used for sensitivity studies. With the samemore »« less

Authors:

^[1];

^[2];

^[1]; Carvalho, P. ^[3]; Delabie, E. ^[4];

^[5]; Hawkes, N. ^[6];

^[7]; Keeling, D. ^[6]; Sertoli, M. ^[6];

^[8]; Szepesi, G. ^[6]; Taylor, D. ^[6]; Thorman, A. ^[6]

National Research Council (CNR), Milan (Italy)
Max Planck Society, Garching (Germany). Max Planck Institute for Plasma Physics
Inst. of Superior Tecnico (IST), Lisbon (Portugal)
Dutch Institute for Fundamental Energy Research (DIFFER), Eindhoven (The Netherlands)
Alternative Energies and Atomic Energy Commission (CEA), Saint-Paul-lez-Durance (France)
Culham Science Centre, Abingdon (United Kingdom). Culham Centre for Fusion Energy (CCFE), EURATOM/UKAEA Fusion Association
KTH Royal Inst. of Technology, Stockholm (Sweden)
General Atomics, San Diego, CA (United States)

Publication Date:: Mon Aug 02 00:00:00 EDT 2021

Research Org.:: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:: USDOE

OSTI Identifier:: 1845767

Grant/Contract Number:: AC05-00OR22725

Resource Type:: Accepted Manuscript

Journal Name:: Nuclear Fusion

Additional Journal Information:: Journal Volume: 61; Journal Issue: 9; Journal ID: ISSN 0029-5515

Publisher:: IOP Science

Country of Publication:: United States

Language:: English

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats


                    Mantica, P., Bonanomi, N., Mariani, A., Carvalho, P., Delabie, E., Garcia, J., Hawkes, N., Johnson, T., Keeling, D., Sertoli, M., Staebler, G. M., Szepesi, G., Taylor, D., and Thorman, A. The role of electron-scale turbulence in the JET tokamak: experiments and modelling.  United States: N. p., 2021. 
Web.  doi:10.1088/1741-4326/ac146e.

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                    Mantica, P., Bonanomi, N., Mariani, A., Carvalho, P., Delabie, E., Garcia, J., Hawkes, N., Johnson, T., Keeling, D., Sertoli, M., Staebler, G. M., Szepesi, G., Taylor, D., & Thorman, A. The role of electron-scale turbulence in the JET tokamak: experiments and modelling.  United States.  https://doi.org/10.1088/1741-4326/ac146e

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                    Mantica, P., Bonanomi, N., Mariani, A., Carvalho, P., Delabie, E., Garcia, J., Hawkes, N., Johnson, T., Keeling, D., Sertoli, M., Staebler, G. M., Szepesi, G., Taylor, D., and Thorman, A. Mon .  
"The role of electron-scale turbulence in the JET tokamak: experiments and modelling".  United States.  https://doi.org/10.1088/1741-4326/ac146e.  https://www.osti.gov/servlets/purl/1845767.

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@article{osti_1845767,

  title        = {The role of electron-scale turbulence in the JET tokamak: experiments and modelling},

  author       = {Mantica, P. and Bonanomi, N. and Mariani, A. and Carvalho, P. and Delabie, E. and Garcia, J. and Hawkes, N. and Johnson, T. and Keeling, D. and Sertoli, M. and Staebler, G. M. and Szepesi, G. and Taylor, D. and Thorman, A.},

  abstractNote = {Dedicated electron heat transport experiments have been carried out in L- and H-mode Deuterium plasmas of the JET-ILW tokamak to identify the amount of electron heat carried by electron-scale electron temperature gradient (ETG) modes. Ion cyclotron resonance heating at different positions has been used to probe the response of the electron temperature inverse gradient length R/LTe to changes in electron heat flux qe, while different amounts of neutral beam heating allowed to scan the ratio of ion to electron temperature Te/Ti, which is a key parameter for the onset of ETGs. Results indicate a steepening of the normalized qe vs R/LTe curve above R/LTe ~ 8 for Te/Ti ≤ 1, suggestive of the ETG onset. Ion-scale gyro-kinetic (GK) simulations match the ion heat flux and the low-R/LTe part of the qe curve, but do not reproduce such steepening at high R/LTe. Multi-scale GK simulations covering both ion and electron scales and including one impurity bundling light and heavy species indicate an ETG contribution only for R/LTe values larger than the experimental ones. Sensitivity studies of such result are difficult to achieve due to limitation in numerical resources. The quasi-linear TGLF model has been used for sensitivity studies. With the same bundled impurity as the GK multi-scale, TGLF shows the qe steepening at much larger R/LTe values than in experiment, but when using the real mix of light impurities neglecting the heavy impurities, TGLF gets closer to the experimental results. Profile simulations with TGLF including both light and heavy impurities show over-prediction of Te profiles and in some cases also of density, but good Ti predictions, confirming issues with the model electron stiffness for these plasmas.},

  doi          = {10.1088/1741-4326/ac146e},

  journal      = {Nuclear Fusion},

  number       = 9,

  volume       = 61,

  place        = {United States},

  year         = {Mon Aug 02 00:00:00 EDT 2021},

  month        = {Mon Aug 02 00:00:00 EDT 2021}

}

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Title: The role of electron-scale turbulence in the JET tokamak: experiments and modelling

Abstract

Citation Formats

The influence of finite drift orbit width on ICRF heating in toroidal plasmas journal, May 2002

Validation of quasi-linear turbulent transport models against plasmas with dominant electron heating for the prediction of ITER PFPO-1 plasmas journal, May 2021

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The global version of the gyrokinetic turbulence code GENE journal, August 2011

Comparison of time dependent simulations with experiments in ion cyclotron heated plasmas journal, July 1993

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Validation of the gyrokinetic model in ITG and TEM dominated L-mode plasmas journal, November 2013

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Investigation of the role of electron temperature gradient modes in electron heat transport in TCV plasmas journal, October 2019

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Multi-scale gyrokinetic simulation of tokamak plasmas: enhanced heat loss due to cross-scale coupling of plasma turbulence journal, December 2015

The role of zonal flows in the saturation of multi-scale gyrokinetic turbulence journal, June 2016

Application of Gaussian process regression to plasma turbulent transport model validation via integrated modelling journal, March 2019

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Impact of electron-scale turbulence and multi-scale interactions in the JET tokamak journal, September 2018

Measuring the plasma composition in tokamaks with metallic plasma-facing components journal, October 2019

Noncircular, finite aspect ratio, local equilibrium model journal, April 1998

The influence of finite drift orbit width on ICRF heating in toroidal plasmas
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Validation of quasi-linear turbulent transport models against plasmas with dominant electron heating for the prediction of ITER PFPO-1 plasmas
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journal, May 2017

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journal, July 2015

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journal, November 2020

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journal, October 2008

Multi-scale gyrokinetic simulation of tokamak plasmas: enhanced heat loss due to cross-scale coupling of plasma turbulence
journal, December 2015

The role of zonal flows in the saturation of multi-scale gyrokinetic turbulence
journal, June 2016

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journal, March 2019

Heat transport driven by the ion temperature gradient and electron temperature gradient instabilities in ASDEX Upgrade H-modes
journal, August 2019

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journal, September 2018

Measuring the plasma composition in tokamaks with metallic plasma-facing components
journal, October 2019

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journal, April 1998