15:45 〜 16:10
[PEM13-10] Simultaneous macroscale and microscale wave–ion interaction in near-earth space plasmas
★Invited Papers
キーワード：wave–ion interaction, EMIC waves, ULF waves
Identifying how energy transfer proceeds from macroscales down to micro-scales in collisionless plasmas is at the forefront of astrophysics and spacephysics. It provides information on the evolution of involved plasma systemsand the generation of high-energy particles in the universe. Here we report twocross-scale energy-transfer events observed by NASA’s Magnetospheric Mul-tiscale spacecraft in Earth’s magnetosphere. In these events, hot ions simul-taneously undergo interactions with macroscale (~105 km) ultra-low-frequencywaves and microscale ( ~ 103 km) electromagnetic-ion-cyclotron (EMIC) waves.The cross-scale interactions cause energy to directly transfer from macro-scales to microscales, and finally dissipate at microscales via EMIC-wave-induced ion energization. The direct measurements of the energy transfer ratein the second event confirm the efficiency of this cross-scale transfer process,whose timescale is estimated to be roughly ten EMIC-wave periods about(1 min). Therefore, these observations experimentally demonstrate thatsimultaneous macroscale and microscale wave-ion interactions provide anefficient mechanism for cross-scale energy transfer and plasma energization inastrophysical and space plasmas