Plasma Waves Associated with Energetic Particles Streaming into the Solar Wind from the Earth's Bow Shock

摘要

In the upstream solar wind, three dominant types of plasma waves are observed associated with energetic particle streams coming from the earth's bow shock: ion-acoustic waves, electron plasma oscillations, and whistler-mode waves. The ion-acoustic waves occur simultaneously with either ion beams or a dispersed ion population in the energy range from approximately 0.5 to greater than 45 keV. These short-wavelength electrostatic waves are very impulsive and the peak amplitudes increase with increasing ion flux and at spatial gradients in the energetic ion densities. The electon plasma oscillations are long-wavelength nearly monochromatic electrostatic wave which are closely correlated with the flux of low energy electrons, especially in the 0.2 - 1.5 keV range. In the presence of only enhanced electron fluxes, the average amplitudes of the electron plasma oscillations approach the peak amplitudes. (Author)