Compressional Alfvén eigenmode instability in NSTX

N. N. Gorelenkov; C. Z. Cheng; E. Fredrickson; E. Belova; D. Gates; S. Kaye; G. J. Kramer; R. Nazikian; R. White

doi:10.1088/0029-5515/42/8/306

Compressional Alfvén eigenmode instability in NSTX

N. N. Gorelenkov, C. Z. Cheng, E. Fredrickson, E. Belova, D. Gates, S. Kaye, G. J. Kramer, R. Nazikian, R. White

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

47 Scopus citations

Abstract

Recent observations of instabilities in MHz frequency range in the National Spherical Toms experiments (NSTX) and their analysis are reported. The instability frequency is correlated with the characteristic Alfvén velocity of the plasma, ν_A. The observed instabilities are explained as compressional Alfvén eigenmodes (CAEs) driven by energetic beam ions. Based on a localized CAE solution, mode frequencies are essentially the compressional Alfvén frequency at the mode location and are given by ω_CAE = ν_Am/r, where m is the poloidal mode number, and r is the minor radius. Energetic ions that are in Doppler shifted cyclotron resonance with CAEs provide free energy to destabilize CAEs. Properties of CAE instability driven by different neutral-beam injection ion distributions are presented.

Original language	English (US)
Pages (from-to)	977-985
Number of pages	9
Journal	Nuclear Fusion
Volume	42
Issue number	8
DOIs	https://doi.org/10.1088/0029-5515/42/8/306
State	Published - Aug 2002

All Science Journal Classification (ASJC) codes

Nuclear and High Energy Physics
Condensed Matter Physics

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Cite this

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title = "Compressional Alfv{\'e}n eigenmode instability in NSTX",

abstract = "Recent observations of instabilities in MHz frequency range in the National Spherical Toms experiments (NSTX) and their analysis are reported. The instability frequency is correlated with the characteristic Alfv{\'e}n velocity of the plasma, νA. The observed instabilities are explained as compressional Alfv{\'e}n eigenmodes (CAEs) driven by energetic beam ions. Based on a localized CAE solution, mode frequencies are essentially the compressional Alfv{\'e}n frequency at the mode location and are given by ωCAE = νAm/r, where m is the poloidal mode number, and r is the minor radius. Energetic ions that are in Doppler shifted cyclotron resonance with CAEs provide free energy to destabilize CAEs. Properties of CAE instability driven by different neutral-beam injection ion distributions are presented.",

author = "Gorelenkov, \{N. N.\} and Cheng, \{C. Z.\} and E. Fredrickson and E. Belova and D. Gates and S. Kaye and Kramer, \{G. J.\} and R. Nazikian and R. White",

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journal = "Nuclear Fusion",

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T1 - Compressional Alfvén eigenmode instability in NSTX

AU - Gorelenkov, N. N.

AU - Cheng, C. Z.

AU - Fredrickson, E.

AU - Belova, E.

AU - Gates, D.

AU - Kaye, S.

AU - Kramer, G. J.

AU - Nazikian, R.

AU - White, R.

PY - 2002/8

Y1 - 2002/8

N2 - Recent observations of instabilities in MHz frequency range in the National Spherical Toms experiments (NSTX) and their analysis are reported. The instability frequency is correlated with the characteristic Alfvén velocity of the plasma, νA. The observed instabilities are explained as compressional Alfvén eigenmodes (CAEs) driven by energetic beam ions. Based on a localized CAE solution, mode frequencies are essentially the compressional Alfvén frequency at the mode location and are given by ωCAE = νAm/r, where m is the poloidal mode number, and r is the minor radius. Energetic ions that are in Doppler shifted cyclotron resonance with CAEs provide free energy to destabilize CAEs. Properties of CAE instability driven by different neutral-beam injection ion distributions are presented.

AB - Recent observations of instabilities in MHz frequency range in the National Spherical Toms experiments (NSTX) and their analysis are reported. The instability frequency is correlated with the characteristic Alfvén velocity of the plasma, νA. The observed instabilities are explained as compressional Alfvén eigenmodes (CAEs) driven by energetic beam ions. Based on a localized CAE solution, mode frequencies are essentially the compressional Alfvén frequency at the mode location and are given by ωCAE = νAm/r, where m is the poloidal mode number, and r is the minor radius. Energetic ions that are in Doppler shifted cyclotron resonance with CAEs provide free energy to destabilize CAEs. Properties of CAE instability driven by different neutral-beam injection ion distributions are presented.

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SP - 977

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JO - Nuclear Fusion

JF - Nuclear Fusion

IS - 8

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Compressional Alfvén eigenmode instability in NSTX

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