Suppression of Nonlinear Chorus Wave Growth by Active Control of Gyroresonant Interactions With Electron Hole Deformation

Nonlinear gyroresonant acceleration is an essential mechanism for the formation of relativistic electrons in Earth's radiation belts, yet we still have only limited knowledge of how electron motion interacts nonlinearly with plasma waves. Here we demonstrate the compelling suppression of whistler-mode chorus emissions as a resonant wave with energetic electrons by tuning an external transmitter signal in space plasmas. Through forcible modification of electron motions via phase trapping by the external waves, the nonlinear gyroresonant current is suppressed along with the electron hole deformation. Moreover, this can decrease the population of relativistic electrons due to the lack of coherent resonant waves seen by the phase-organized electrons. Understanding such nonlinear wave suppression effects is crucial for a potential active control of Earth's plasma environment. Since the strong radiation in space can cause health risks for astronauts and satellite anomalies of electronics, understanding toward the active control of the particle populations is in increasing demand for sustainable space industry growth. The gyroresonant interactions between energetic electrons and whistler-mode waves play important roles in the acceleration mechanism of the Earth's radiation belt electrons. We find that transmitter signals as an external wave source in space plasmas can utilize the changing of nonlinear electron motion by stimulating electrons in a phase space. We show that nonlinear whistler mode chorus wave excitation, which is the resonant wave source for energetic electrons, can effectively be suppressed by deforming the shape of electron holes to control resonant currents in the phase space. This mechanism is crucial for understanding the active control of Earth's plasma environments. Chorus waves can be suppressed by inhibition of coherent interactions with resonant electrons due to adding external transmitter waves The external waves having a different frequency from the maximum linear growth can become incoherent from the point of view of electrons The external waves can precipitate the seed electrons, then this reduces the anisotropy of particles and hence inhibits wave growth