Drift-wave spectra in plasmas with magnetic shear

Journal Article · Wed Jun 01 04:00:00 EDT 1983 · Phys. Fluids; (United States)

DOI:https://doi.org/10.1063/1.864317· OSTI ID:6078930

Rogister, A; Hasselberg, G

The nonlinear radial eigenmode equation governing the evolution of drift waves in a weakly turbulent state is obtained under the assumption that ion nonlinear scattering (nonlinear ion Landau damping) is the dominant saturation mechanism. The poloidal spectrum is to be derived from the eigenvalue equation. The local character of the interaction in frequencies allows the transformation of the otherwise integral wave kinetic equation (i.e., the eigenvalue equation) into a system of two first-order differential equations coupling the spectra I(k/sub theta/) and I(k/sup dagger//sub theta/) if ..omega..(k/sup dagger//sub theta/) = ..omega..(k/sub theta/). The density fluctuation spectrum is obtained analytically in the limit of the small temperature ratio T/sub i//T/sub e/. Some features are: (i) the spectral index at high mode numbers agrees well with experimental values; (ii) the long-wavelength spectrum peaks at k/sub theta/a/sub s/approx. =0.62 (a/sub s/ equivalentsound Larmor radius), (iii) the cross-field diffusion is mostly induced by the high-mode-number fluctuations, whereas the major contribution to the density fluctuations is in the long wavelengths; (iv) the frequency spectrum of the beat waves peaks at ..omega.. = 0 (they then have a convective cell character); and (v) the turbulence level is a factor L/sub n//L/sub s/ (ratio of density and shear lengths) smaller than with former theories.

• Research Organization: Institut fuer Plasmaphysik der Kernforschungsanlage Juelich GmbH, Association EURATOM--KFA, 5170 Juelich, Federal Republic of Germany
• OSTI ID: 6078930
• Journal Information: Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 26:6; ISSN PFLDA
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700108* -- Fusion Energy-- Plasma Research-- Wave Phenomena
CHARGED PARTICLES
DAMPING
DIFFERENTIAL EQUATIONS
DRIFT INSTABILITY
EIGENVALUES
EQUATIONS
FLUCTUATIONS
INSTABILITY
IONS
LANDAU DAMPING
MAGNETIC FIELDS
NONLINEAR PROBLEMS
PLASMA
PLASMA DENSITY
PLASMA INSTABILITY
PLASMA MICROINSTABILITIES
SATURATION
SHEAR
TURBULENCE
VARIATIONS