Stark Fields from Ions in a Plasma

The effect of electric and magnetic plasma microfields on elementary many-body processes in plasmas is considered. As detected first by Inglis and Teller in 1939, the electric microfield controls several elementary processes in plasmas as transitions, line shifts and line broadening. We concentrate here on the many-particle processes ionization, recombination, and fusion and study a wide area of plasma parameters. In the first part the state of art of investigations on microfield distributions is reviewed in brief. In the second part, various types of ionization processes are discussed with respect to the influence of electric microfields. It is demonstrated that the processes of tunnel and rescattering ionization by laser fields as well as the process of electron collisional ionization may be strongly influenced by the electric microfields in the plasma. The third part is devoted to processes of microfield action on fusion processes and the effects on three-body recombination are investigated. It is shown that there are regions of plasma densities and temperatures, where the rate of nuclear fusion is accelerated by the electric microfields. This effect may be relevant for nuclear processes in stars. Further, fusion processes in ion clusters are studied. Finally we study in this section three-body recombination effects and show that an electric microfield influences the three-body electron-ion recombination via the highly excited states. In the fourth part, the distribution of the magnetic microfield is investigated for equilibrium, nonequilibrium, and non-uniform magnetized plasmas. We show that the field distribution in a neutral point of a non-relativistic ideal equilibrium plasma is similar to the Holtsmark distribution for the electrical microfield. Relaxation processes in nonequilibrium plasmas may lead to additional microfields. We show that in turbulent plasmas the broadening of radiative electron transitions in atoms and ions, without change of the principle quantum number, may be due to the Zeeman effect and may exceed Doppler and Stark broadening as well. Further it is shown that for optical radiation the effect of depolarization of a linearly polarized laser beams propagating through a magnetized plasma may be rather strong.

Section: Influence Of Two-particle Kepler Motionmentioning

confidence: 99%

Elementary Many‐Particle Processes in Plasma Microfields

Romanovsky¹,

Ébeling

2006

“…In recent papers it was argued that the electric microfield low frequency part (due to the ion dynamics) also influences the fusion rates [3] and the rates for the three-body electronion recombination [4] in dense plasmas. The opposite limiting case of infinite coupling strength was considered by Mayer [5,6] within the ion sphere model. The opposite limiting case of infinite coupling strength was considered by Mayer [5,6] within the ion sphere model.…”

Section: Introductionmentioning

confidence: 99%

“…Holtsmark's work on the electric microfield distribution was restricted to ideal plasmas. The opposite limiting case of infinite coupling strength was considered by Mayer [5,6] within the ion sphere model. Within this model the central ion undergoes harmonic oscillations around the center of the negatively charged ion sphere.…”

Section: Introductionmentioning

confidence: 99%

Electric Microfield Distribution in Two-Component Plasmas. Theory and Simulations

Ortner

Valuev

Ébeling

2000

The distribution of the electric microfield at a charged particle moving in a two-component plasma is calculated. The theoretical approximations are obtained via the parameter integration technique and using the screened pair approximation for the generalized radial distribution function. It is shown that the two-component plasma microfield distribution shows a larger probability of high microfield values than the corresponding distribution of the commonly used OCP model. The theory is checked by quasiclassical molecular-dynamics simulations. For the simulations a corrected Kelbg pseudopotential has been used.

“…In a preceding work we studied the influence of Levy noise on the velocity distribution and discussed applications on rate processes [6]. Here we will take into account that in a dense plasma the stochastic forces have a more complicated distribution including a main body of Gaussian character [7][8][9]. The reason are at first the stochastic forces acting on charges from the side of atomic species and secondly by small angle collisions with other charged particles.We will make the simplifying assumption that the real noise in a plasma may be approximated by the sum of a Gaussian noise and a Levy noise.…”

Section: Introductionmentioning

confidence: 99%

Velocity Distributions and Kinetic Equations for Plasmas Including Levy Type Power Law Tails

Ébeling¹,

Romanovsky

Sokolov

2009

We develop the assumption that deviations from Maxwell distributions which are often observed in nonequilibrium plasmas may be described by convoluted Gauss-Levy distributions. We derive these distributions by solving Langevin equations for the velocities including linear damping and two additional noise sources, centrally distributed over Levy and Gauss functions. Here the Levy noise should model the action of the electrical microfields or other strong near collisions and the Gaussian noise the usual small-angle stochastic scattering processes. It is shown that in a transient time the probability distribution function first looks like a Levy function. Then the central part of the distribution begins to smooth and assumes a Gaussian shape, the wings of the distribution remain Levy type. Estimates and physical applications of the high-energetic wings to rate processes are discussed.