Volume 49, Nº 1 (2023)

Under conditions of glow discharge in the strong magnetic field, three-dimensional dust structures were created in the He, Ne, and Ar working gases in three types of dust traps (in standing stratum, in the region of current channel narrowing, and in the region of nonuniform magnetic field). These structures are stable in the fields of the order of 2 T. In all traps, the rotation dynamics have been studied of horizontal (perpendicular to the magnetic field) cross sections of dust structures, their angular velocities has been measured, and the nonuniform angular velocity distributions in the dust structure volumes have been measured. For the first time, for the trap in the region of current channel narrowing, the data are presented in the range of magnetic inductions of up to 2.5 T. Such magnetic fields correspond to the Ne+ ion magnetization parameter of approximately 2 and the ion cyclotron radius comparable to the shielding distance. In the fields higher than 1.5 T, the angular velocity of the structure rotation increased to 50 s–1, which is a record-breaking fast rotation of dusty plasma. For each of the traps under study, the geometrical features of the dust structures are described.

The thermodynamic stability of a multicomponent plasma is studied on the basis of the Ornstein–Zernike integral equations for a multicomponent fluid. A transition is made to the one-component Ornstein–Zernike equation for the most non-ideal subsystem for a plasma with any number of components under the conditions of applicability of the Debye approximation for direct correlation functions for all plasma components, except for the most non-ideal subsystem. It is shown that all pair correlation functions, charge–charge and number–number structure factors remain positive for all argument values in the entire studied range of the non-ideality parameter of the most non-ideal subsystem. The conditions for the violation of the thermodynamic stability of a three-component dusty plasma are studied for different signs of the charge of dust particles and their different number density.

The mechanism of modulational interaction of various wave modes in the meteoroid tails is described. Modulational instability of different oscillation modes can lead to the appearance of a number of effects observable in the meteoroid tails, such as the electrophonic noises. In particular, the modulational instability of the electromagnetic waves from the meteoroid shock wave related to the dust-acoustic mode, along with the modulational instability of the lower hybrid and Langmuir waves, can cause these effects. Waves that subsequently transform into an acoustic wave reaching the Earth’s surface can be generated in the first case. Magnetic fields with a magnitude comparable to that of the magnetic fields experimentally detected by means of magnetometers can appear in the latter two cases. Transverse electromagnetic oscillations that can be perceived as electrophonic noises heard simultaneously with the meteoroid passage when they reach the Earth’s surface can propagate as well. We analyze the influence of meteor flashes on parameters of the dusty plasma of the meteoroid tails depending on the altitude of the meteor-body passage. Characteristic concentrations of dust particles in the meteoroid tails during flashes as a function of altitude are estimated. Using the example of modulational instability of electromagnetic waves related to the dust-acoustic mode, we demonstrate how increased concentration of dust particles during flashes influences the growth rate of the instability and conditions of its development.

We present a theoretical model describing possible mechanism of formation and evolution of plasma–dust clouds observed in the Martian ionosphere by the Mars Science Laboratory Curiosity rover in March 2021. The model describes sedimentation of dust particles in the supersaturated carbon dioxide vapor, growth of dust seeds due to carbon dioxide nucleation, charging of dust particles, and changes in electron and ion number densities of the ionospheric plasma over time in particular. It is demonstrated that formation of the layered structure of the dust cloud the characteristic sedimentation time of which is on the order of several minutes can be illustrated within the framework of the proposed model. Characteristic size of the dust particles are calculated and found to be consistent with the results of the measurements. In addition, characteristic charges of dust particles in the presence and in the absence of the photoelectric effect are calculated. It is demonstrated that dust particles acquire negative charge in the absence of the photoelectric effect. Simultaneously, number densities of plasma electrons and ions decrease. In the presence of the photoelectric effect, particles containing metallic impurities carry a positive charge. In the process, number density of plasma electrons increases, while ion number density continues to decrease.

Experimental results are presented on deposition of charged particles that imitate the levitating dust of regolith (dusty plasma) on the Moon on metal plates. The experiment was based on the analogy between the physical–chemical properties of the processes that develop in regolith during microwave discharge excited by the radiation of a powerful gyrotron in the powder of regolith (lunar dust) and the processes that occur on the Moon during the bombardment of its surface by micrometeorites. The action is studied of the levitating dust cloud on plates made from molybdenum and tantalum with a size of 10 × 40 mm. The results are compared with the experiment on deposition of lunar dust on plates from stainless steel. It is shown that dust particles in the shape of spheroids of different sizes are deposited on the plates. The size distribution of these particles and their chemical composition are those of lunar regolith. It is found that the uniformity of dust deposition can be controlled by preliminary processing of the metal plates by the low-temperature plasma of a direct piezodischarge. It is shown that the levitating dust obtained under laboratory conditions (ensembles of charged regolith particles) can be used in imitation experiments on surface modification of different materials and in the development of methods for cleaning the space equipment during Moon missions.

The results are presented from experiments on determining the size of melamine formaldehyde dust particles during their long-term stay in the dust-plasma trap formed in the glow discharge in argon. It is shown that in 30 min, the diameter of particles decreases from 7.3 (initial diameter) to 3.5 μm; accordingly, the particles lose almost 90% of their mass. Three stages were distinguished of particle degradation in time. In the stage of maximum rate of particle size decrease, particles lose 20 pg/min. The data obtained are compared with the available measurement results for discharges in neon. It was ascertained that the rate of particle size decrease depends on the mass of plasma-forming gas. In argon and krypton, at the identical discharge parameters, the degradation of particles of the same initial size occurs faster than in neon. However, the starting time of intense mass loss more strongly depends on the particle size than on the type of gas. The data are compared with the existing physical model of particle degradation, and recommendations are proposed for performing long-term experiments with melamine formaldehyde particles.

Plasma dust formations with liquid particles (microdroplets) are studied. Methods used for the formation of liquid microdroplets in a vacuum are analyzed in the study, and a laboratory bench for studying liquid plasma dust formations is constructed. The phenomenon is examined and photographed.