Особенность в точке перехода от равновесной к метастабильной фазе металлического расплава
Dust particles under certain conditions can acquire kinetic energy of the order of 10 eV and higher, far above the temperature of gas and temperatures of ions and electrons in the discharge. Furthermore, significant difference of mean horizontal and vertical energy is observed. Such difference can be explained by the energy transfer between degrees of freedom of a dusty plasma system. The proposed mechanism of energy transfer between vertical and horizontal motion is based on parametric resonance. A system of equations describing dust particles' motion with account of dust particle charge fluctuations and features of the discharge near-electrode layer is formulated. Molecular dynamics simulations of dust particles' system are performed. Dependences of magnitude of transferred energy and horizontal energy growth rate on system parameters are obtained.
The small number of dust particles in the system and their large kinetic energy make it impossible to use the notion of “temperature” to describe the dynamics of dust particles in gas discharge without substantiation. We simulated the isolated and open systems of dust particles based on the molecular dynamics method and suggested the substantiation of applying the term “temperature” to describe the dynamics of the system of dust particles in the gas discharge plasma. The closeness of the equilibrium velocity distribution for a small number of particles and the Maxwell distribution for isolated and open systems is shown. It is found that the average kinetic energy precisely coincides with the velocity distribution parame ter of the dust particles. The necessity of separation the temperature of the horizontal motion and the temperature of the vertical motion of dust particles is shown.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.