The Spectrum Of Square Crystal Lattice In A Two-dimensional Binary Dusty Plasma

Plasmas exist widely in the universe.Plasmas containing charged solid or liquid particles are called complex plasmas(or dust plasmas).Because of plasma environment,the influx of positive and negative charges causes the particles to carry positive or negative charges.In a strongly coupled complex plasma,the particles are restricted in one layer to form a hexagonal lattice,known as a plasma crystal.The discovery of plasma crystals has increased interest in the study of complex plasmas.Binary complex plasmas contain two different particles which,under certain conditions,can form two-dimensional square lattices.Via langevin dynamics simulation and stability of the lattice tests index ?8,we discussed two kinds of different the lattice stability condition of particle charge,and got a square lattice to form stable interval.The ratio of the particle charge and also accord with the theoretical calculation results very well.Under the condition of strong vertical constraint to suppress the plane external mode,we obtain the equations of Newton's second law about two kinds of particles by analyzing their forces,and further deduce and calculate the dispersion relation of lattice waves in the longitudinal and transverse.We make the wave vector K be the direction along the X-axis and the direction with an angle of 45° from the X-axis respectively,and the theoretical results clearly show a total of 8 branches of the acoustic branch and optical branch,among which the longitudinal wave contains 4 branches and the transverse wave contains 4 branches.In order to verify the accuracy of the theoretical curve,the results are compared with the phonon spectrum obtained by Langevin dynamics simulation,and the consistency is high,which verifies the correctness of the theory.Then a further study is carried out to explore whether there are differences in phonon spectra in the square lattice formed by different particles,namely,two kinds of particles with different charge ratios and mass ratios.Therefore,by changing the charge ratio and mass ratio of the two kinds of particles,we compare the dispersion relation under different parameters in theory and find the relation between the dispersion relation and the charge ratios and mass ratios of the two kinds of particles.This work fully discusses the conditions for forming a two-dimensional binary complex plasma square lattice.The dispersion relation of square crystal lattice is deduced theoretically and its accuracy is verified by comparison with molecular dynamics simulation,and then further research found the relationship between the dispersion relation and the charge ratios and mass ratios of the two kinds of particles and the changes,which provided a theoretical basis for future related research.After completing the research on the spectra of two-dimensional and binary complex plasma square lattice,we expanded the research content from two-dimensional to three-dimensional,and trained the neural network model to help us analyze the lattice structure by deep learning.We built the VGG16 model and used the computer-generated training set containing BCC,FCC and HCP structures for training,and then used the same training set as the test set for testing.The results so far look less than ideal,with the highest accuracy rate reaching just 48 per cent.In order to improve the test accuracy of the model and apply it in future experiments,it can be considered to continue to adjust the parameters to train the new model or find out the deficiencies of the training set,and use a more complete training set with more obvious characteristics for training.