Gyroresonance Between Electromagnetic Ion Cyclotron Waves and Particles in a Multi-ion Plasma

【摘要】 <正> The gyroresonant interaction between electromagnetic ion cyclotron （EMIC） wavesand energetic particles was studied in a multi-ion （H⁺, He⁺, and O⁺） plasma. The minimumresonant energy E_min, resonant wave frequency ω, and pitch angle diffusion coefficient D_αα werecalculated at the center location of the symmetrical ring current: r 3.5R_E with R_E the Earth’sradius. E_min is found to decrease rapidly from 10 MeV to a few keV with the increase in ω in threebands: H⁺-band, He⁺-band and O⁺-band. Moreover, EMIC waves have substantial potential toscatter energetic （～100 keV） ions （mainly H⁺ and He⁺） into the loss cone and yield precipitationloss, suggesting that wave-particle interactions contribute to ring current decay.更多还原

【Abstract】 The gyroresonant interaction between electromagnetic ion cyclotron （EMIC） waves and energetic particles was studied in a multi-ion （H⁺, He⁺, and O⁺） plasma. The minimum resonant energy E_min, resonant wave frequency ω, and pitch angle diffusion coefficient D_αα were calculated at the center location of the symmetrical ring current: r 3.5R_E with R_E the Earth’s radius. E_min is found to decrease rapidly from 10 MeV to a few keV with the increase in ω in three bands: H⁺-band, He⁺-band and O⁺-band. Moreover, EMIC waves have substantial potential to scatter energetic （～100 keV） ions （mainly H⁺ and He⁺） into the loss cone and yield precipitation loss, suggesting that wave-particle interactions contribute to ring current decay.更多还原