Gyrofluid turbulence models with kinetic effects

Technical Report · Tue Dec 01 04:00:00 EST 1992

DOI:https://doi.org/10.2172/10114655· OSTI ID:10114655

Dorland, W; Hammett, G W

Nonlinear gyrofluid equations are derived by taking moments of the nonlinear, electrostatic gyrokinetic equation. The principal model presented includes evolution equations for the guiding center n, u{parallel}, T{parallel}, and T{perpendicular} along with an equation expressing the quasineutrality constraint. Additional evolution equations for higher moments are derived which may be used if greater accuracy is desired. The moment hierarchy is closed with a Landau-damping model which is equivalent to a multi-pole approximation to the plasma dispersion function, extended to include finite Larmor radius effects. In particular, new dissipative, nonlinear terms are found which model the perpendicular phase-mixing of the distribution function along contours of constant electrostatic potential. These ``FLR phase-mixing`` terms introduce a hyperviscosity-like damping {proportional_to} k{sub {perpendicular}}{sup 2}{vert_bar}{Phi}{sub {rvec k}}{rvec k} {times}{rvec k}{prime}{vert_bar} which should provide a physics-based damping mechanism at high k{perpendicular}{rho} which is potentially as important as the usual polarization drift nonlinearity. The moments are taken in guiding center space to pick up the correct nonlinear FLR terms and the gyroaveraging of the shear. The equations are solved with a nonlinear, three dimensional initial value code. Linear results are presented, showing excellent agreement with linear gyrokinetic theory.

• Research Organization: Princeton Univ., NJ (United States). Plasma Physics Lab.
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 10114655
• Report Number(s): PPPL--2874; ON: DE93005727
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700330
700370
DISPERSION RELATIONS
DISTRIBUTION FUNCTIONS
KINETIC EQUATIONS
LANDAU DAMPING
LARMOR RADIUS
MHD EQUILIBRIUM
NONLINEAR PROBLEMS
PLASMA FLUID AND MHD PROPERTIES
PLASMA INSTABILITY
PLASMA KINETICS, TRANSPORT, AND IMPURITIES
TOKAMAK DEVICES
TURBULENT FLOW