Kinetic Alfvén turbulence below and above ion cyclotron frequency

Abstract Novel internal measurements and analysis of ion cyclotron frequency range fast-ion driven modes in DIII-D are presented. Observations, including internal density fluctuation (ñ) measurements obtained via Doppler Backscattering, are presented for modes at low harmonics of the ion cyclotron frequency localized in the edge. The measurements indicate that these waves, identified as coherent Ion Cyclotron Emission (ICE), have high wave number, _⊥ρ_fast ≳ 1, consistent with the cyclotron harmonic wave branch of the magnetoacoustic cyclotron instability (MCI), or electrostatic instability mechanisms. Measurements show extended spatial structure (at least ~ 1/6 the minor radius). These edge ICE modes undergo amplitude modulation correlated with edge localized modes (ELM) that is qualitatively consistent with expectations for ELM-induced fast-ion transport.

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Harmonic generation and parametric decay in the ion-cyclotron frequency range

The Physics of Fluids ◽

10.1063/1.864898 ◽

1984 ◽

Vol 27 (9) ◽

pp. 2205 ◽

Cited By ~ 22

Author(s):

F. Skiff ◽

K. L. Wong ◽

M. Ono

Keyword(s):

Harmonic Generation ◽

Cyclotron Frequency ◽

Frequency Range ◽

Parametric Decay ◽

Ion Cyclotron

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Finite Larmor radius wave equations in Tokamak plasmas in the ion cyclotron frequency range

Plasma Physics and Controlled Fusion ◽

10.1088/0741-3335/31/5/004 ◽

1989 ◽

Vol 31 (5) ◽

pp. 723-757 ◽

Cited By ~ 69

Author(s):

M Brambilla

Keyword(s):

Wave Equations ◽

Cyclotron Frequency ◽

Larmor Radius ◽

Tokamak Plasmas ◽

Frequency Range ◽

Finite Larmor Radius ◽

Ion Cyclotron

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Excitation electric field inhomogeneities in a cubic ion cyclotron resonance cell: ion motion for away from the cyclotron frequency

International Journal of Mass Spectrometry and Ion Processes ◽

10.1016/0168-1176(93)80034-c ◽

1993 ◽

Vol 125 (2-3) ◽

pp. 95-126 ◽

Cited By ~ 20

Author(s):

Dale W. Mitchell ◽

Bryan A. Hearn ◽

Stephen E. DeLong

Keyword(s):

Electric Field ◽

Cyclotron Resonance ◽

Cyclotron Frequency ◽

Ion Cyclotron Resonance ◽

Ion Motion ◽

Ion Cyclotron ◽

Resonance Cell

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Finite-frequency surface waves on current sheets

Journal of Plasma Physics ◽

10.1017/s0022377800015798 ◽

1991 ◽

Vol 45 (3) ◽

pp. 389-406 ◽

Cited By ~ 2

Author(s):

K. P. Wessen ◽

N. F. Cramer

Keyword(s):

Magnetic Field ◽

Dispersion Relation ◽

Surface Waves ◽

Cyclotron Frequency ◽

Low Frequency ◽

Dielectric Tensor ◽

Magnetic Field Direction ◽

Field Reversal ◽

Ion Cyclotron ◽

The Magnetic Field

The dispersion relation for low-frequency surface waves at a current sheet between two magnetized plasmas is derived using the cold-plasma dielectric tensor with finite ion-cyclotron frequency. The magnetic field direction is allowed to change discontinuously across the sheet, but the plasma density remains constant. The cyclotron frequency causes a splitting of the dispersion relation into a number of mode branches with frequencies both less than and greater than the ion-cyclotron frequency. The existence of these modes depends in particular upon the degree of magnetic field discontinuity and the direction of wave propagation in the sheet relative to the magnetic field directions. Sometimes two modes can exist for the same direction of propagation. The existence of modes undamped by Alfvén resonance absorption is predicted. Analytical solutions are obtained in the low-frequency and magnetic-field-reversal limits. The solutions are obtained numerically in the general case.

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