scholarly journals Symmetric Set of Transport Coefficients for Collisional Magnetized Plasma

2021 ◽  
Vol 126 (7) ◽  
Author(s):  
James D. Sadler ◽  
Christopher A. Walsh ◽  
Hui Li
1986 ◽  
Vol 36 (3) ◽  
pp. 313-328 ◽  
Author(s):  
F. Cozzani ◽  
W. Horton

The transport theory of a high-energy ion species injected isotropically in a magnetized plasma is considered for arbitrary ratios of the high-energy ion cyclotron frequency to the collisional slowing down time. The assumptions of (i) low fractional density of the high-energy species and (ii) average ion speed faster than the thermal ions and slower than the electrons are used to decouple the kinetic equation for the high-energy species from the kinetic equations for background ions and electrons. The kinetic equation is solved by a Chapman–Enskog expansion in the strength of the gradients; an equation for the first correction to the lowest-order distribution function is obtained without scaling a priori the collision frequency with respect to the gyrofrequency. Various transport coefficients are explicitly calculated for the two cases of a weakly and a strongly magnetized plasma.


2020 ◽  
Vol 58 (1) ◽  
pp. 441-481 ◽  
Author(s):  
Valery M. Nakariakov ◽  
Dmitrii Y. Kolotkov

The corona of the Sun is a unique environment in which magnetohydrodynamic (MHD) waves, one of the fundamental processes of plasma astrophysics, are open to a direct study. There is striking progress in both observational and theoretical research of MHD wave processes in the corona, with the main recent achievements summarized as follows: ▪  Both periods and wavelengths of the principal MHD modes of coronal plasma structures, such as kink, slow and sausage modes, are confidently resolved. ▪  Scalings of various parameters of detected waves and waveguiding plasma structures allow for the validation of theoretical models. In particular, kink oscillation period scales linearly with the length of the oscillating coronal loop, clearly indicating that they are eigenmodes of the loop. Damping of decaying kink and standing slow oscillations depends on the oscillation amplitudes, demonstrating the importance of nonlinear damping. ▪  The dominant excitation mechanism for decaying kink oscillations is associated with magnetized plasma eruptions. Propagating slow waves are caused by the leakage of chromospheric oscillations. Fast wave trains could be formed by waveguide dispersion. ▪  The knowledge gained in the study of coronal MHD waves provides ground for seismological probing of coronal plasma parameters, such as the Alfvén speed, the magnetic field and its topology, stratification, temperature, fine structuring, polytropic index, and transport coefficients.


2000 ◽  
Vol 10 (03) ◽  
pp. 409-440 ◽  
Author(s):  
B. LUCQUIN-DESREUX

Here we consider a magnetized plasma composed of electrons of low mean density and of one species of multicharged ions. Starting with the Vlasov–Fokker–Planck equations for both particles, we derive a diffusion model for the electrons, with explicit transport coefficients which are related to the ions. Finally, we study the kinetic boundary layers in the case of a bounded domain in space variables. For that purpose, we are led to study a Milne problem and to introduce a generalized extrapolation length.


1999 ◽  
Vol 62 (2) ◽  
pp. 129-144 ◽  
Author(s):  
S. R. BROWN ◽  
M. G. HAINES

The modified Fokker–Planck collision operator for partially degenerate electrons was derived in an earlier paper [J. Plasma Phys.58, 577 (1997)]. This is now employed to study linear electron transport for a partially degenerate, magnetized plasma. Because polynomial expansions can yield incorrect transport coefficients owing to lack of resolution of the small fraction of low-energy unmagnetized electrons, a numerical discrete-ordinate scheme is employed. The inclusion of electron–electron collisions advances the model beyond that of Lee and More, and in the classical limit agrees with the results of Epperlein and Haines.


1976 ◽  
Vol 16 (2) ◽  
pp. 193-227 ◽  
Author(s):  
John A. Krommes ◽  
Carl Oberman

A general formalism for describing two-time fluctuations in magnetized plasma is presented. Two-time expectations of one-body operators (phase functions) are written in terms of the phase space density autocorrelation functionwhere δN is the fluctuation in the singular Klimontovich microdensity. It is shown that is the first member of a set of two-time quantitieswhich collectively obeys the linearized BBGKY cumulant hierarchy in the (Xi, t) variables, with initial conditions successively smaller in the plasma parameter . We study in detail the case of fluctuations in thermal equilibrium, although the general formalism holds also for the non-equilibrium case. To lowest order in εP, Γ obeys the linearized Vlasov equation. From this are recovered all of Rostoker's results for fluctuations excited by Cherenkov emission and absorbed by Landau damping, as well as a constructive proof of the test particle superposition principle. To first order, Γ obeys (in the Markovian approximation) the linearized Balescu-Guernsey-Lenard equation. For frequencies and wavenumbers in the hydrodynamic regime, the velocity moments of Γ obey linearized fluid equations with classical transport coefficients (i.e. essentially those computed by Braginskii in the 3-D case). It has been found that the classical theory is in disagreement with certain computer and laboratory experiments performed in strong magnetic fields. This defect is attributed to the absence in the classical theory of contributions to the collision operator, hence transport coefficients, of fluctuations long-lived on the Vlasov scale. Analogous difficulties arise in the theory of hydrodynamics in neutral fluids. To improve the plasma theory, a renormalization of the two-time hierarchy is proposed which sums selected terms from all orders in εP and thus treats the hydrodynamic fluctuations self-consistently. The resulting theory retains appropriate fluid conservation laws, thereby avoiding erroneous results encountered in certain diffusing orbit theories, when the fluid viscosity is indiscriminantly replaced by the test particle diffusion coefficient. In order to explain the results of the computer simulations, the theory is applied in part 2 to the problem of anomalous hydrodynamic contributions to the transport coefficients.


1976 ◽  
Vol 16 (2) ◽  
pp. 229-260 ◽  
Author(s):  
John A. Krommes ◽  
Carl Oberman

The general formalism for treating two-time fluctuations in magnetized plasma, developed in part 1 of this series, is applied to the case of anomalous cross-field transport in 2-D, strongly magnetized, thermal equilibrium systems. For (where εP is the plasma parameter), classical predictions for the ion shear viscosity and test particle diffusion coefficients are dominated by the anomalous contributions of low frequency, long wavelength hydrodynamic fluctuations (convective cells). The anomalous transport is discussed from the points of view of (a) kinetic theory; (b) the assumption of long-time local thermal equilibrium (Landau-Placzek method); and (c) a renormalized mode-coupling version of the generalized Langevin equation. The results of all these approaches are in agreement, and they predict that the transport coefficients scale with magnetic field B as 1/B for, and as independent of B forin good agreement with the computer simulations of Okuda & Dawson. The transport is weakly non-Markovian, the Green-Kubo integrands decay non-classically for long times as [t ln (t)]−½, and the test particle ‘;diffusion’ coefficient does not asymptotically approach a constant for t → ∞.


1974 ◽  
Author(s):  
D. Bolmont ◽  
J. Salmon ◽  
M. Valton

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