Dispersion relation of surface waves generated by a relativistic plasma stream in an infinite duct surrounded by vacuum is derived by means of relativistic Vlasov equation. The kinematic boundary condition imposed on ...Dispersion relation of surface waves generated by a relativistic plasma stream in an infinite duct surrounded by vacuum is derived by means of relativistic Vlasov equation. The kinematic boundary condition imposed on the distribution function, the specular reflection conditions on the four sides of duct, can be satisfied by placing infinite number of fictitious surface charge sheets spaced by the duct widths. By placing appropriate fictitious surface charge sheets one can effectively deal with the extended electric field introduced in the Vlasov equation and treat kinetically the surface waves in semi-infinite, slab, and duct plasmas on equal ground. The relativistic duct dispersion relation is compared with the earlier non-relativistic surface wave dispersion relation.展开更多
Plasma echo theory is revisited to apply it to a semi-bounded plasma. Spatial echoes associated with plasma surface wave propagating in a semi-bounded plasma are investigated by calculating the second order electric f...Plasma echo theory is revisited to apply it to a semi-bounded plasma. Spatial echoes associated with plasma surface wave propagating in a semi-bounded plasma are investigated by calculating the second order electric field produced by external charges and satisfying the boundary conditions at the interface. The boundary conditions are two-fold: the specular reflection condition and the electric boundary condition. The echo spots are determined in terms of the perpendicular coordinate to the interface and the parallel coordinate along which the wave propagates. This improves the earlier works in which only the perpendicular coordinate is determined. In contrast with the echo in an infinite medium, echoes in a bounded plasma can occur at various spots. The diversity of echo occurrence spots is due to the discontinuity of the electric field at the interface that satisfies the specular reflection boundary condition. Physically, the diversity appears to be owing to the reflections of the waves from the interface.展开更多
We derive the collisionless Landau damping in a plasma by satisfying the causal requirement that the susceptibility function of the plasma for time t should be nil. The causality condition should be satisfied by the s...We derive the collisionless Landau damping in a plasma by satisfying the causal requirement that the susceptibility function of the plasma for time t should be nil. The causality condition should be satisfied by the susceptibility function of a plasma no matter what equations we employ to describe the plasma. Thus we conclude that the fundamental reason of the collisionless damping can be traced to the causality. As an example, we derive the collisionless damping of ion acoustic wave in a plasma by employing fluid equations.展开更多
文摘Dispersion relation of surface waves generated by a relativistic plasma stream in an infinite duct surrounded by vacuum is derived by means of relativistic Vlasov equation. The kinematic boundary condition imposed on the distribution function, the specular reflection conditions on the four sides of duct, can be satisfied by placing infinite number of fictitious surface charge sheets spaced by the duct widths. By placing appropriate fictitious surface charge sheets one can effectively deal with the extended electric field introduced in the Vlasov equation and treat kinetically the surface waves in semi-infinite, slab, and duct plasmas on equal ground. The relativistic duct dispersion relation is compared with the earlier non-relativistic surface wave dispersion relation.
文摘Plasma echo theory is revisited to apply it to a semi-bounded plasma. Spatial echoes associated with plasma surface wave propagating in a semi-bounded plasma are investigated by calculating the second order electric field produced by external charges and satisfying the boundary conditions at the interface. The boundary conditions are two-fold: the specular reflection condition and the electric boundary condition. The echo spots are determined in terms of the perpendicular coordinate to the interface and the parallel coordinate along which the wave propagates. This improves the earlier works in which only the perpendicular coordinate is determined. In contrast with the echo in an infinite medium, echoes in a bounded plasma can occur at various spots. The diversity of echo occurrence spots is due to the discontinuity of the electric field at the interface that satisfies the specular reflection boundary condition. Physically, the diversity appears to be owing to the reflections of the waves from the interface.
文摘We derive the collisionless Landau damping in a plasma by satisfying the causal requirement that the susceptibility function of the plasma for time t should be nil. The causality condition should be satisfied by the susceptibility function of a plasma no matter what equations we employ to describe the plasma. Thus we conclude that the fundamental reason of the collisionless damping can be traced to the causality. As an example, we derive the collisionless damping of ion acoustic wave in a plasma by employing fluid equations.
