Amplification of whistler waves by trapped relativistic electrons in the magnetosphere

摘要

Summary form only given. Relativistic electrons trapped in the radiation belts have a loss-cone velocity distribution. A loss-cone negative mass instability process to amplify whistler waves by those electrons in the bulk of the energy distribution is studied. An differential-integral equation, which governs the temporal evolution of the whistler wave field amplitude, is derived. The numerical results show that whistler waves can be amplified by more than 20 dB, agreeing with the experimental results. This amplification process reduces considerably the required field intensity of injected whistler wave for the purpose of precipitating electrons in MeV range. This suggests an optimal approach applying the chaotic scattering process to reduce the population of very energetic electrons trapped in the magnetosphere. It is using less-energetic electrons (e.g., >100 KeV electrons) to amplify injected whistler waves through loss-cone negative mass instability and then using the amplified waves to scatter undesired energetic electrons (e.g., MeV electrons) into the loss cone.