Details

Autor(en) / Beteiligte

• Ni, Binbin
• Cao, Xing
• Shprits, Yuri Y.
• Summers, Danny
• Gu, Xudong
• Fu, Song
• Lou, Yuequn

Titel

Hot Plasma Effects on the Cyclotron‐Resonant Pitch‐Angle Scattering Rates of Radiation Belt Electrons Due to EMIC Waves

Ist Teil von

• Geophysical research letters, 2018-01, Vol.45 (1), p.21-30

Ort / Verlag

Washington: Blackwell Publishing Ltd

Erscheinungsjahr

2018

Link zum Volltext

Quelle

Wiley Online Library

Beschreibungen/Notizen

• To investigate the hot plasma effects on the cyclotron‐resonant interactions between electromagnetic ion cyclotron (EMIC) waves and radiation belt electrons in a realistic magnetospheric environment, calculations of the wave‐induced bounce‐averaged pitch angle diffusion coefficients are performed using both the cold and hot plasma dispersion relations. The results demonstrate that the hot plasma effects have a pronounced influence on the electron pitch angle scattering rates due to all three EMIC emission bands (H+, He+, and O+) when the hot plasma dispersion relation deviates significantly from the cold plasma approximation. For a given wave spectrum, the modification of the dispersion relation by hot anisotropic protons can strongly increase the minimum resonant energy for electrons interacting with O+ band EMIC waves, while the minimum resonant energies for H+ and He+ bands are not greatly affected. For H+ band EMIC waves, inclusion of hot protons tends to weaken the pitch angle scattering efficiency of >5 MeV electrons. The most crucial differences introduced by the hot plasma effects occur for >3 MeV electron scattering rates by He+ band EMIC waves. Mainly due to the changes of resonant frequency and wave group velocity when the hot protons are included, the difference in scattering rates can be up to an order of magnitude, showing a strong dependence on both electron energy and equatorial pitch angle. Our study confirms the importance of including hot plasma effects in modeling the scattering of ultra‐relativistic radiation belt electrons by EMIC waves. Key Points Both cold and hot dispersion relations are used in the calculations of EMIC wave‐induced bounce‐averaged pitch angle diffusion coefficients Hot plasma effects can significantly influence the scattering loss of radiation belt electrons induced by all the three EMIC wave bands The differences of diffusion coefficients are caused by the changes of resonant frequency and wave group velocity