Multi-case study of particle distribution functions associated with ion cyclotron waves at ballooning-interchange heads

Recent THEMIS and MMS spacecraft observations confirmed the kinetic simulations showing that the kinetic Ballooning/Interchange Instability (BICI) may lead to off-equator electromagnetic ion-cyclotron waves.  The ion-cyclotron waves appeared to ripple the growing ballooning-interchange heads and to erode and thin the magnetotail current sheet at ion scales. As this wave activity may be important for initiating magnetic reconnection in the magnetotail, we aim at collecting a number of high-resolution MMS ion observations with clear signatures of the electromagnetic ion-cyclotron waves, and at investigating the particle behavior caused by the waves. Particularly, we analyze the properties of the electromagnetic ion cyclotron waves and search for signatures of wave interaction with resonant particles using partial ion distribution functions and their moments.