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Discusses the construction of distinctive collisional transport laws for plasma edge by deriving and solving a novel kinetic equation. Retention of radial diffusion and parallel flow of particles by new edge ordering; Assumption that radial diffusion results from classical Coulomb collisions.

Gyro-fluid equations are velocity space moments of the gyrokinetic equations. Special gyro-Landau-fluid closures have been developed that include the damping due to kinetic resonances by fitting to the collisionless local plasma response functions. This damping allows for accurate linear eigenmodes to be computed with a relatively low number of velocity space moments compared to the number of velocity quadrature points in gyrokinetic codes. However, none of the published gyro-Landau-fluid closure schemes considers the Onsager symmetries of the resulting quasi-linear fluxes as a constraint. Onsager symmetry guarantees that the matrix of diffusivities is positive definite, an important property for the numerical stability of a transport solver. A two parameter real closure for improving the accuracy of low resolution gyro-fluid equations, which preserves the Onsager symmetry and allows higher velocity space moments, is presented in this paper. The new linear gyro-fluid system (GFS) is used to extend the TGLF quasi-linear transport model so that it can compute the energy and momentum fluxes due to parallel magnetic fluctuations, completing the transport matrix. The GFS equations do not use a bounce average approximation. The GFS equations are fully electromagnetic with general flux surface magnetic geometry, pitch angle scattering for electron collisions, and subsonic equilibrium toroidal rotation. Using GFS eigenmodes in the quasi-linear TGLF model will be shown to yield a more accurate match to fluxes computed by CGYRO turbulence simulations. Prospects for future applications of a quasi-linear theory to new plasma transport regimes and magnetic confinement devices in addition to tokamaks are opened by the flexibility of the GFS eigensolver. [ABSTRACT FROM AUTHOR]

We consider the transport properties of polar direct-gap semiconductors in an electric field, specializing the numerical calculation of the general theory to the case of n-doped III-nitrides, in particular, GaN, AlN, and InN. The nonequilibrium thermodynamic state of these materials—characterized by the variables so-called quasitemperature, quasichemical potential, and drift velocity of the carriers, and the quasitemperatures of longitudinal optical and acoustical phonons—is studied. The evolution equations of these variables—which are highly nonlinear—are derived, and the transient regime and the ensuing steady state are analyzed. The nonlinear transport is characterized and its main properties are discussed. In one case comparison with a recent Monte Carlo calculation is made and good agreement is obtained. In this paper we mainly consider the ultrafast transient, and in the following paper the steady state. [ABSTRACT FROM AUTHOR]

The ion and electron thermal diffusivities have been inferred from measured density and temperature profiles in the edge of a DIII-D [J. Luxon, Nucl. Fusion 42, 614 (2002)] discharge with a low confinement (L-mode) stage followed by a high confinement (H-mode) stage free of edge localized modes. Conductive heat flux profiles used to construct the inferred thermal diffusivities were calculated taking into account heat convection, radiation, atomic physics effects of recycling neutrals, ion-electron equilibration, and neutral beam heating. The inferred thermal diffusivities were compared with theoretical predictions. [ABSTRACT FROM AUTHOR]