资源环境科技发展态势分析平台

Although foreshock transients can generate strong magnetospheric Pc5 ULF waves, whether they can modulate the energy of magnetospheric ions is still poorly understood. In this paper, we analyze the strong magnetospheric ion energy modulations in a foreshock transient event on 30 October 2008, based on the magnetospheric observations by THEMIS A and D in the prenoon sector. ULF wave‐induced drift accelerated the cold ions up to ∼ 10 keV and the enhanced ion fluxes have wave‐like patterns. There is another portion of enhanced ion fluxes from ∼0.8 to ∼10 keV but with strong energy dispersions in this event. By comparing the observations and the theoretical prediction, we for the first time found that the drift‐bounce resonances played a major role in modulating the energy of those ions with energy dispersions, during the interactions between the ions and the foreshock transient‐driven Pc5 ULF wave with growing and damping effects.