Analytic stability boundaries for compressional and global Alfven eigenmodes driven by fast ions. II. Interaction via Landau resonance.

Lestz, J. B.; Gorelenkov, N. N.; Belova, E. V.; Tang, S. X.; Crocker, N. A.

doi:10.11578/1608306

Title: Analytic stability boundaries for compressional and global Alfven eigenmodes driven by fast ions. II. Interaction via Landau resonance.

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Abstract

Conditions for net fast ion drive are derived for beam-driven, co-propagating, sub-cyclotron compressional (CAE) and global (GAE) Alfven eigenmodes driven by the Landau resonance with super-Alfvenic fast ions. Approximations applicable to realistic neutral beam distributions and mode characteristics observed in spherical tokamaks enable the derivation of marginal stability conditions for these modes. Such conditions successfully reproduce the stability boundaries found from numerical integration of the exact expression for local fast ion drive/damping. Coupling between the CAE and GAE branches of the dispersion due to finite \omega/\omega_{ci} and k_\parallel/k_\perp is retained and found to be responsible for the existence of the GAE instability via this resonance. Encouraging agreement is demonstrated between the approximate stability criterion, simulation results, and a database of NSTX observations of co-CAEs.

Authors:

Lestz, J. B.; Gorelenkov, N. N.; Belova, E. V.; Tang, S. X.; Crocker, N. A.

PPPL

Publication Date:: Tue Dec 31 23:00:00 EST 2019

DOE Contract Number:: AC02-09CH11466

Research Org.:: Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY

OSTI Identifier:: 1608306

DOI:: https://doi.org/10.11578/1608306

Citation Formats


                    Lestz, J. B., Gorelenkov, N. N., Belova, E. V., Tang, S. X., and Crocker, N. A. Analytic stability boundaries for compressional and global Alfven eigenmodes driven by fast ions. II. Interaction via Landau resonance..  United States: N. p., 2019. 
        Web.  doi:10.11578/1608306.

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                    Lestz, J. B., Gorelenkov, N. N., Belova, E. V., Tang, S. X., & Crocker, N. A. Analytic stability boundaries for compressional and global Alfven eigenmodes driven by fast ions. II. Interaction via Landau resonance..  United States.  doi:https://doi.org/10.11578/1608306

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                    Lestz, J. B., Gorelenkov, N. N., Belova, E. V., Tang, S. X., and Crocker, N. A. 2019.  
"Analytic stability boundaries for compressional and global Alfven eigenmodes driven by fast ions. II. Interaction via Landau resonance.".  United States.  doi:https://doi.org/10.11578/1608306.  https://www.osti.gov/servlets/purl/1608306. Pub date:Tue Dec 31 23:00:00 EST 2019

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@article{osti_1608306,

  title        = {Analytic stability boundaries for compressional and global Alfven eigenmodes driven by fast ions. II. Interaction via Landau resonance.},

  author       = {Lestz, J. B. and Gorelenkov, N. N. and Belova, E. V. and Tang, S. X. and Crocker, N. A.},

  abstractNote = {Conditions for net fast ion drive are derived for beam-driven, co-propagating, sub-cyclotron compressional (CAE) and global (GAE) Alfven eigenmodes driven by the Landau resonance with super-Alfvenic fast ions. Approximations applicable to realistic neutral beam distributions and mode characteristics observed in spherical tokamaks enable the derivation of marginal stability conditions for these modes. Such conditions successfully reproduce the stability boundaries found from numerical integration of the exact expression for local fast ion drive/damping. Coupling between the CAE and GAE branches of the dispersion due to finite \omega/\omega_{ci} and k_\parallel/k_\perp is retained and found to be responsible for the existence of the GAE instability via this resonance. Encouraging agreement is demonstrated between the approximate stability criterion, simulation results, and a database of NSTX observations of co-CAEs.},

  doi          = {10.11578/1608306},

  journal      = {},

  number       = ,

  volume       = ,

  place        = {United States},

  year         = {Tue Dec 31 23:00:00 EST 2019},

  month        = {Tue Dec 31 23:00:00 EST 2019}

}

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DOI: https://doi.org/10.11578/1608306

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