A closed set of moment equations for the plasma density, velocity and
pressure is proposed by imposing linear closure for the heat flux and
viscosity. The formulation is valid for arbitrary finite Larmor radius
parameter k(perpendicular to)rho (k(perpendicular to) is the perpendi
cular wave vector, rho is the particle Larmor radius) and retains main
convective nonlinearities. Reduced moment equations relevant to the d
rift-wave modes are derived in the low frequency limit (omega much les
s than omega(B), omega(B) is the particle cyclotron frequency). (C) 19
95 American Institute of Physics.