Effect of external magnetic field and friction force on the dynamic properties of a system of charged particles

Abstract

The paper describes the algorithm of the method of molecular (Langevin) dynamics, the modeled system and the main parameters characterizing the system. The presented mathematical model is built for a magnetically active dusty plasma taking into account the influence of the friction force due to the presence of the environment (buffer plasma). To solve the equation of motion of dust particles, a modified numerical Verlet scheme obtained by the authors of the work was used. The mathematical model is built for a two-dimensional system, the particles of which interact using the Yukawa potential. A detailed analysis of the autocorrelation functions of velocities and their Fourier transforms of dust particles for different values ​​of the parameters of the magnetic field, coupling and friction is carried out. It was found that an increase in friction causes a decrease in the dominant peak at a fixed value of the magnetic field parameter. This peak corresponds to the combined effect of the magnetic field and strong correlations in the system; the complete disappearance of the peak corresponding to cyclotron oscillations was found when the friction force is not taking into account. It is shown that, with low friction, an increase in the magnetic field leads to a monotonic increase in the amplitude of the dominant peak and with a large value of friction, in contrast to its decrease, which is explained by us that the decay of ultrasonic waves in the medium increases with increasing frequency, however, a more detailed description of this effect may be a topic for further research. Key words: molecular dynamic method, Verlet algorithm velocity autocorrelation functions, external magnetic field, friction force