Irina Paiva-Veretennicoff

Kinetic theory of the plasma-dynamical modes and the transport coefficients of a relativistic plasma

The kinetic equation of an inhomogeneous relativistic plasma, consisting of an electron gas and a radiation field, is studied with particular regard to its eigenvalues in the hydrodynamical limit. The treatment is classical for the particles and quantum-mechanical for the field oscillators.

On the relativistic plasma-dynamical and hydrodynamical normal modes

A plasma and a neutral fluid behave in very different ways in the so-called hydrodynamical limit, when submitted to a long-wavelength disturbance. Both cases can be treated however in the same way if the plasma-dynamical equations are properly regularized. The frequencies and damping rates of both relativistic neutral-fluid modes and relativistic plasma modes are discussed in detail. A new relativistic plasma effect is exhibited as an anomalous, wavelength-independent damping coefficient of longitudinal and transverse plasma oscillations. This effect originates from the contribution of the electric field to the heat flow in a relativistic plasma.

Stochastic simulation of the gas diffusion in the air phase of the human lung

The solution of the diffusion equation in the gas phase of the human lung is very difficult because of the structure of the bronchial tree. It is shown by means of physical arguments, how one can reduce the diffusion equation to a simple one-dimensional form. The solution is then obtained by a stochastic simulation, which is easily realized on a digital computer.

Anomalous transport coefficients in a turbulent plasma

A general self-consistent framework is developed for the calculation of transport coefficients in a collisionless, weakly turbulent plasma. These coefficients characterize the response to a perturbation away from a quasi-steady turbulent state, which is assumed to exist as a result of the stabilization of the linear instabilities. It is shown that a purely hydrodynamical description does not exist for plasmas: the macroscopic picture must include non-conserved quantities, which lead to the plasmadynamical (or ‘two-fluid’) picture of the system. The number of independent transport coefficients, necessary for the macroscopic characterization of the plasma, is correspondingly increased as compared with a two-component mixture of two ordinary fluids. The typical turbulent contributions to the transport coefficients are clearly exhibited.

Electrostatic-field fluctuations and form factors in multi-component non-equilibrium plasmas

Taking the Langevin approach to the evaluation of kinetic fluctuations with respect to a Maxwellian distribution characterized by different constant temperatures and mean velocities per species, the form factors and electrostatic field fluctuations of a multi-component plasma are derived. It is shown that the generalization of the Callen-Welton theorem for non-equilibrium systems, derived using thermodynamical arguments, has to be revised. Explicit values of the intensities of the electrostatic-field fluctuations are calculated, in the high-and low-frequency regimes. The former do not require any modelling of the collision integral. The latter have been calculated with a model that is more correct and simpler, than the Bhatnagar-Gross-Krook model.

Relativistic plasma-dynamical equations and plasma-dynamical normal modes

Abstract The equations of evolution of a relativistic plasma and radiation are derived from the macroscopic conservation laws. The delicate concepts of a spatially homogeneous and of a weakly inhomogeneous system are defined in a covariant way. By using standard procedures of non-equilibrium thermodynamics, a closed set of linearized relativistic plasma-dynamical equations coupled to Maxwells equations is obtained. The plasma-dynamical normal modes are derived from these equations. They are discussed in detail, with special emphasis on the deep differences appearing between these modes and the hydrodynamical modes of a normal fluid. These differences are due both to collective plasma motions and to relativistic effects.

Macroscopic plasmadynamical modes in a complete two-fluid description

The paper contains an analysis of the linearized plasma-dynamical equations, including the energy conservation equations, and accounting completely for all the dissipative mechanisms, in the absence of external fields. The eigenvalues of the 14 plasmadynamical modes are obtained systematically in terms of the transport coefficients of the plasma.

Is Galilean relativistic thermodynamics well defined

Abstract It is shown that the ambiguity in the transformation laws of some thermodynamic quantities, is not a consequence of special relativity.