(ricevuto il 2 Luglio 1990; manoscritto revisionato ricevuto il 9 Aprile 1991) Summary. --In this paper we formulate a master equation approach describing a D + T thermonuclear plasma in a lumped phase space. From the first moments of this master equation and performing the pass to the continuous limit the evolution equations for the expected phase space ion densities emerge. Also we have obtained the evolution equations of the equal time correlation and covariance functions. Finally we have deduced the hydrodynamic equations that arise from a master equation approach.PACS 52.25 -Plasma properties.
-Introduction.In the study of far from equilibrium hydrodynamic fluctuations, a master equation (ME) approach seems to be the natural and necessary method of description of such fluctuations [1,2]. However, such description must include the feedback of the fluctuations on the average behaviour [3]. The ME approach which accomplish this goal was developed by Brenig and Van der Broeck [4,5], which extended the Logan, Kac and Keizer [6,7] works, to include the effect of large fluctuations.Under plasma conditions, the motion of charged particles is determined by two types of interactions: i) close interactions, treated generally as binary collisions; ii) collective long-range interactions with many particles, that can be represented by electric and magnetic fields [8][9][10] which can be calculated with electromagnetic theory using the charge and current distribution, however we must observe that these electromagnetic fields are stochastic because they depend on the distribution of charged particles, and therefore the fluctuations in the distribution of charge particles give rise to fluctuations in these afore-mentioned electromagnetic fields which in turn affect the charge distributions.The simplest characterization of the nonequilibrium plasma uses a one-fluid magnetohydrodynamic picture (MHD). These equations are essentially those of the hydrodynamics, supplemented by terms appropriate to a conducting fluid, and by MaxweU's equations for the electromagnetic fields [11]. The next level of sophistica-89 -Il Nuovo Cimento D.1325