Two-dimensional phase transition in a strongly nonideal dusty plasma

Laser-induced melting of two-dimensional dusty plasma system in RF discharge

“…As it has been shown in our previous studies [25][26][27][28] , the value of the function g 6 (r/r p ) is completely determined by the number of the appearing defects, that is why it is more convenient and reasonable to use normalized bond-angular correlation function in the form of g 6 * (r/r p ) = g 6 (r/r p )/N 6 , where N 6 is a fraction of particles with 6 nearest neighbors (see Fig. 3 in our work 28 ).…”

“…For an ideal hexagonal structure the function g 6 ( r ) ≡ 1, while it decreases with distance for other phase states of the system. The asymptotics of dimensionless pair g 2 ( r/r p ) and bond-angular g 6 ( r/r p ) correlation functions can be used to analyze the phase state of the system 27 , 28 . Thus, for two-dimensional non-ideal systems, the spatial decay of peaks of pair correlation functions in an ideal crystal is described by the power law g 2 ∝ ( r / r p ) -η at η < 1/3, in the hexatic phase and the liquid, by the exponential dependence g 2 ∝ exp(- μr/r p ) at μ = μ h ≡ const and μ > μ h , respectively.…”

“…Researchers have been looking for the evidence of hexatic phase among a wide range of two-dimensional systems , including monolayers of electrons on the surface of liquid helium 14 , polymer colloids [15][16][17] , magnetic bubbles in thin films [18][19][20] , liquid crystals [21][22][23] , superconductors 24 , as well as in dusty plasmas . Some experimental and numerical works have shown a good agreement with KTHNY theory [25][26][27][28] , but others haven't. The reason of that might be in out-of-plane fluctuations 29,30 , finite-size effects 31,32 or different types of inhomogeneities, commonly observed in experiments during melting process.…”

Dynamic Effects of Laser Action on Quasi-Two-Dimensional Dusty Plasma Systems of Charged Particles

“…With a further increase in the power of the laser radiation, the formation of a directional motion of dust particles in the region of the laser beam exposure was observed. From the analysis of the trajectories of the particle motions (see Figure 2), as well as of the distribution of their velocities in the structure (see Figure 3), we can consider the threshold nature of the flow, which is consistent with the experimental results obtained in [6,7]. Under the influence of a pushing laser with a power close to the critical value, we observed a deformation of the structure, however the flow still did not occur.…”

“…In previous work [4,5], the Brownian motion of dust grains in plasma was investigated by video recording of the particle dynamics, so that the friction coefficient of dust particles in the buffer gas was measured. One can also use lasers to heat dust particles and Molecules 2020, 25, 3375 2 of 8 increase their kinetic energy due to the photophoretic force; thus, phase transitions in colloidal plasma systems can be observed [6,7].…”