The ponderomotive force of an electromagnetic wave in a collisional plasma

The nonlinear propagation of a circularly polarized, electromagnetic wave in a collisional, infinite, magnetized plasma is considered. The presence of collisions leads to spatial variation in the amplitude of the wave field which gives rise to a time-independent ponderomotive force. The ponderomotive potential for a left (right) circularly polarized wave attains a maximum at the ion (electron) cyclotron frequency. In the vicinity of the cyclotron frequency it is shown to be always positive. A decrease in both the particle density and the real and imaginary parts of the complex wavenumber is shown to result from the effect of the ponderomotive forc

Particle motion and energy dissipation spectra in a planetary ball mill

The charge motion and energy dissipation in a planetary ball mill are investigated using the Discrete Element Method (DEM). In addition to simulations of the grinding media (balls) only, different fill levels of the ground material (fine particles) are considered to examine its effect on the mill charge dynamics. The energy dissipation spectra determined from the DEM simulations provide insights into the comminution processes that occur in the planetary mill, and how they are influenced by the fill level and size distribution of the fine particles

Study of the charging of a blast furnace with a rotating chute using the discrete element method

A numerical study of the charging process of a full-scale blast furnace, based on the Discrete Element Method, is presented. This study concentrates on the granular flow in a rotating chute employed to distribute appropriately the charge in the furnace. Detailed analysis of the results of numerical simulations has been undertaken to determine specific phenomena of importance to the charging process. Validation of the numerical results is obtained by comparison with experimental measurements of the position of the charge stream after exiting from the chute. The numerical results are shown to be in excellent qualitative and quantitative agreement with the experimental observations

Single-particle motion under the influence of the perpendicular ponderomotive force

The motion of a single particle under the influence of the ponderomotive force directed perpendicular to the external magnetostatic field is analysed. By solving the exact equation of motion for a specific applied electromagnetic field, the resultant ponderomotive drift is compared with the prediction of a single-particle theory using the oscillation-centre approximation. The regime of validity of this theory is discussed. It is shown that, for certain values of the amplitude and frequency of the electromagnetic field, the particle motion is unstable and therefore the concept of a single-particle ponderomotive force is meaningles