Nonlinear coherent structures of electrostatic ion cyclotron wave induced by a moving obstacle

The excitations of nonlinear electrostatic ion cyclotron waves arising from a steadily moving charged obstacle are investigated in collisionless plasmas. In the weakly nonlinear and dispersive limit, it is shown that the moving obstacle-induced excitations can be described by a forced Ostrovsky-type model equation. The exact analytical solution predicts that the nonlinear equation does have a periodic solution for a specific analytic form of the obstacle. The computational results are noteworthy, which predict the generation of coherent nonlinear structures, such as bipolar, sawtooth, and multi-harmonic, of the electric field at the transcritical speed of the obstacle along with the wave packets. The results agree well with the astrophysical observations in auroral plasmas.

Automated summary

This study investigates the excitation of nonlinear electrostatic ion cyclotron waves caused by a moving charged obstacle in collisionless plasmas. In the weakly nonlinear and dispersive limit, it is found that the excitations can be described by a forced Ostrovsky-type model equation. The exact analytical solution predicts the periodic solution of the nonlinear equation for a specific form of the obstacle. The computational results show the generation of coherent nonlinear structures, such as bipolar, sawtooth, and multi-harmonic, of the electric field at the transcritical speed of the obstacle along with the wave packets, which agree well with astrophysical observations in auroral plasmas.