skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

This content will become publicly available on June 21, 2020

Title: Modeling of high harmonic fast wave scenarios for NSTX Upgrade

Abstract

NSTX-Upgrade will operate with toroidal magnetic fields ( B T) up to 1 T, nearly twice the value used in the experiments on NSTX, and the available neutral beam injection (NBI) power will be doubled. The doubling of B T while retaining the 30 MHz RF source frequency has moved the heating regime from the high harmonic fast wave (HHFW) regime used in NSTX to the mid harmonic fast wave regime. By making use of the full wave code AORSA (assuming a Maxwellian plasma), this work explores different HHFW scenarios for two possible antenna frequencies (30 and 60 MHz) and with and without NBI. Both frequencies have large electron absorption for large wave toroidal number particularly without NBI. With the presence of NBI, the fast ions absorption can be dominant in some scenarios. Therefore, a competition between electron and fast ion absorption is clearly apparent partially explaining why in previous NSTX HHFW experiments, a less efficient electron heating was observed. Moreover at the toroidal field of 1 T, a direct thermal ion damping might be possible under the condition when the ion temperature is larger than electron temperature. In general, the electron and ion absorption are found very sensitive tomore » the ratio of electron and ion temperature. The impact of the hydrogen species is also studied showing that, for hydrogen concentration below 2%, the hydrogen absorption is not significant. However, a larger hydrogen concentration could open up new HHFW heating scenarios in NSTX-U. Launching at high toroidal wave number appears to be one way to significantly reduce the ion damping and in turn to obtain large electron damping in the core which can play an important role in the transport studies for NSTX-U. Lastly, an higher magnetic field could also playing a role in increasing the electron temperature and consequently the electron absorption. Indeed a magnetic field scan is also shown and discussed.« less

Authors:
 [1];  [1];  [2]
  1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  2. XCEL Engineering Inc., Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
Contributing Org.:
This work was supported by the SciDAC Center for Wave- Plasma Interactions under DE-FC02-01ER54648 and the US DOE under DE-AC02-CH0911466
OSTI Identifier:
1558764
Grant/Contract Number:  
SC0018090; AC02-CH0911466
Resource Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 59; Journal Issue: 8; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; HHFW; NSTX-U; fast wave; RF heating

Citation Formats

Bertelli, N., Ono, M., and Jaeger, E. F. Modeling of high harmonic fast wave scenarios for NSTX Upgrade. United States: N. p., 2019. Web. doi:10.1088/1741-4326/ab1d7f.
Bertelli, N., Ono, M., & Jaeger, E. F. Modeling of high harmonic fast wave scenarios for NSTX Upgrade. United States. doi:10.1088/1741-4326/ab1d7f.
Bertelli, N., Ono, M., and Jaeger, E. F. Fri . "Modeling of high harmonic fast wave scenarios for NSTX Upgrade". United States. doi:10.1088/1741-4326/ab1d7f.
@article{osti_1558764,
title = {Modeling of high harmonic fast wave scenarios for NSTX Upgrade},
author = {Bertelli, N. and Ono, M. and Jaeger, E. F.},
abstractNote = {NSTX-Upgrade will operate with toroidal magnetic fields (BT) up to 1 T, nearly twice the value used in the experiments on NSTX, and the available neutral beam injection (NBI) power will be doubled. The doubling of BT while retaining the 30 MHz RF source frequency has moved the heating regime from the high harmonic fast wave (HHFW) regime used in NSTX to the mid harmonic fast wave regime. By making use of the full wave code AORSA (assuming a Maxwellian plasma), this work explores different HHFW scenarios for two possible antenna frequencies (30 and 60 MHz) and with and without NBI. Both frequencies have large electron absorption for large wave toroidal number particularly without NBI. With the presence of NBI, the fast ions absorption can be dominant in some scenarios. Therefore, a competition between electron and fast ion absorption is clearly apparent partially explaining why in previous NSTX HHFW experiments, a less efficient electron heating was observed. Moreover at the toroidal field of 1 T, a direct thermal ion damping might be possible under the condition when the ion temperature is larger than electron temperature. In general, the electron and ion absorption are found very sensitive to the ratio of electron and ion temperature. The impact of the hydrogen species is also studied showing that, for hydrogen concentration below 2%, the hydrogen absorption is not significant. However, a larger hydrogen concentration could open up new HHFW heating scenarios in NSTX-U. Launching at high toroidal wave number appears to be one way to significantly reduce the ion damping and in turn to obtain large electron damping in the core which can play an important role in the transport studies for NSTX-U. Lastly, an higher magnetic field could also playing a role in increasing the electron temperature and consequently the electron absorption. Indeed a magnetic field scan is also shown and discussed.},
doi = {10.1088/1741-4326/ab1d7f},
journal = {Nuclear Fusion},
number = 8,
volume = 59,
place = {United States},
year = {2019},
month = {6}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on June 21, 2020
Publisher's Version of Record

Save / Share:

Works referenced in this record:

Overview of the physics and engineering design of NSTX upgrade
journal, July 2012


Overview of NSTX Upgrade initial results and modelling highlights
journal, June 2017

  • Menard, J. E.; Allain, J. P.; Battaglia, D. J.
  • Nuclear Fusion, Vol. 57, Issue 10, Article No. 102006
  • DOI: 10.1088/1741-4326/aa600a

A component test facility based on the spherical tokamak
journal, November 2005


Remote Handling and Plasma Conditions to Enable Fusion Nuclear Science R&D Using a Component Testing Facility
journal, August 2009

  • Peng, Y. K. M.; Burgess, T. W.; Carroll, A. J.
  • Fusion Science and Technology, Vol. 56, Issue 2
  • DOI: 10.13182/FST09-A9034

Prospects for pilot plants based on the tokamak, spherical tokamak and stellarator
journal, August 2011


Fusion nuclear science facilities and pilot plants based on the spherical tokamak
journal, August 2016


High harmonic fast waves in high beta plasmas
journal, November 1995


High harmonic fast wave heating efficiency enhancement and current drive at longer wavelength on the National Spherical Torus Experiment
journal, May 2008

  • Hosea, J.; Bell, R. E.; LeBlanc, B. P.
  • Physics of Plasmas, Vol. 15, Issue 5
  • DOI: 10.1063/1.2837051

Advances in high-harmonic fast wave physics in the National Spherical Torus Experiment
journal, May 2010

  • Taylor, G.; Bell, R. E.; Hosea, J. C.
  • Physics of Plasmas, Vol. 17, Issue 5
  • DOI: 10.1063/1.3371956

Spectral effects on fast wave core heating and current drive
journal, June 2009


Short-Scale Turbulent Fluctuations Driven by the Electron-Temperature Gradient in the National Spherical Torus Experiment
journal, August 2008


Suppression of Electron Temperature Gradient Turbulence via Negative Magnetic Shear in NSTX
journal, February 2011


High-Harmonic Fast-Wave Power Flow along Magnetic Field Lines in the Scrape-Off Layer of NSTX
journal, July 2012


The role of rectified currents in far-field RF sheaths and in SOL losses of HHFW power on NSTX
journal, August 2017


Full wave simulations of fast wave heating losses in the scrape-off layer of NSTX and NSTX-U
journal, May 2014


All-orders spectral calculation of radio-frequency heating in two-dimensional toroidal plasmas
journal, May 2001

  • Jaeger, E. F.; Berry, L. A.; D’Azevedo, E.
  • Physics of Plasmas, Vol. 8, Issue 5
  • DOI: 10.1063/1.1359516

A generalized plasma dispersion function for electron damping in tokamak plasmas
journal, October 2016

  • Berry, L. A.; Jaeger, E. F.; Phillips, C. K.
  • Physics of Plasmas, Vol. 23, Issue 10
  • DOI: 10.1063/1.4964766

Predicting High Harmonic Ion Cyclotron Heating Efficiency in Tokamak Plasmas
journal, September 2011


Fast wave heating in the NSTX-Upgrade device
conference, January 2014

  • Bertelli, N.; Jaeger, E. F.; Berry, L.
  • RADIOFREQUENCY POWER IN PLASMAS: Proceedings of the 20th Topical Conference, AIP Conference Proceedings
  • DOI: 10.1063/1.4864550

Exploration of high harmonic fast wave heating on the National Spherical Torus Experiment
journal, May 2003

  • Wilson, J. R.; Bell, R. E.; Bernabei, S.
  • Physics of Plasmas, Vol. 10, Issue 5
  • DOI: 10.1063/1.1560921

High harmonic ion cyclotron heating in DIII-D: Beam ion absorption and sawtooth stabilization
journal, October 1999


Fast wave current drive at high ion cyclotron harmonics on DIII-D
journal, November 2001

  • Petty, C. C.; Baity, F. W.; deGrassie, J. S.
  • Plasma Physics and Controlled Fusion, Vol. 43, Issue 12
  • DOI: 10.1088/0741-3335/43/12/308

A full wave theory of high-harmonic fast wave absorption in high-beta plasmas
journal, June 1998

  • Lashmore-Davies, C. N.; Fuchs, V.; Cairns, R. A.
  • Physics of Plasmas, Vol. 5, Issue 6
  • DOI: 10.1063/1.872901

High-harmonic fast magnetosonic wave coupling, propagation, and heating in a spherical torus plasma
journal, May 1999

  • Menard, J.; Majeski, R.; Kaita, R.
  • Physics of Plasmas, Vol. 6, Issue 5
  • DOI: 10.1063/1.873483

Recent Fast Wave Coupling and Heating Studies on NSTX, with Possible Implications for ITER
conference, January 2009

  • Hosea, J. C.; Bell, R. E.; Feibush, E.
  • RADIO FREQUENCY POWER IN PLASMAS: Proceedings of the 18th Topical Conference, AIP Conference Proceedings
  • DOI: 10.1063/1.3273706

Edge loss of high-harmonic fast-wave heating power in NSTX: a cylindrical model
journal, September 2017


Scenario development during commissioning operations on the National Spherical Torus Experiment Upgrade
journal, February 2018