Turbulent Wave Field Research Articles

One-dimensional numerical study of charged particle trajectories in turbulent electrostatic wave fields

The motion of a charged particle in strong turbulent wave fields is studied numerically over many trapping periods. Transitions between three velocity states, namely the trapped state, and the states of high and low velocity, characterize the motion.

The interaction of homogeneous wave turbulence and a magnetohydrodynamic tangential discontinuity

The interaction of homogeneous wave turbulence and a magnetohydrodynamic tangential discontinuity is studied. Attention is focused on the turbulent shear stress produced as a result of such an interaction. A magnetohydrodynamic description is used which is believed to be adequate for plasma problems in interplanetary space. As a model for wave turbulence, it is assumed that the turbulent wave field is made up of the seven modes of magnetohydrodynamic waves. They are the entropy waves, the Alfvn waves (two independent modes), the fast and slow waves (each with two independent modes). It is found that to a first approximation the turbulent shear stress acting on the surface of discontinuity is linearly proportional to the energy density of the fluctuating magnetic field and to the kinetic energy density of the plasma fluctuations. On applying the present theory to the problem of interaction between the turbulent waves in the magnetosheath and the magnetopause, it is found that the turbulent shear stress produced is too weak to produce any large-scale internal magnetospheric convection as was previously contemplated.

Summary-introduction: Collision-free plasmas

In the corona regions of stars the ratio of the mean free path for interparticle collision to the gyro radius becomes very large. Under these conditions the transport processes in the plasma become dominated by plasma turbulence. This phenomenon can be described in terms of a kinetic theory of a random distribution of waves. The structure of a shock-wave under these conditions has been considered. Even at densities as low as 102 particles per cm3 the thickness of such a shock-wave should be very thin, less than 100 km. The effects of such a turbulent wave field on reducing the electrical conductivity has also been considered. It seems possible that appreciable diffusion of the magnetic field relative to the plasma could occur under some astronomical conditions.