Analysis of EMIC-wave-moderated flux limitation of measured energetic ion spectra in multispecies magnetospheric plasmas

作者：Mauk B H^*

来源：Geophysical Research Letters, 2013, 40(15): 3804-3808.

DOI：10.1002/grl.50789

• Van Allen Probes
• radiation belts
• energetic ions
• ring current

A differential Kennel-Petschek (KP) flux limit for magnetospheric energetic ions is devised taking into account multiple ion species effects on electromagnetic ion cyclotron (EMIC) waves that scatter the ions. The idea is that EMIC waves may limit the highest ion intensities during acceleration phases of storms and substorms (similar to hour) while other mechanisms (e.g., charge exchange) may account for losses below those limits and over longer periods of time. This approach is applied to published Earth magnetosphere energetic ion spectra (similar to keV to similar to 1MeV) for radial positions (L) 3 to 6.7 R-E. The flatness of the most intense spectral shapes for <100keV indicate sculpting by just such a mechanism, but modifications of traditional KP parameters are needed to account for maximum fluxes up to 5.4 times greater than expected. Future work using the new capabilities of the Van Allen Probes mission will likely resolve outstanding uncertainties.

• 出版日期2013-8-16