Magnetopause Kelvin-Helmholtz (KH) waves are believed to mediate solar wind plasma transport via small-scale mechanisms. Vortex-induced reconnection (VIR) was predicted in simulations and recently observed using NASA’s Magnetospheric Multiscale (MMS) mission data. Flux Transfer Events (FTEs) produced by VIR at multiple locations along the periphery of KH waves were also predicted in simulations but detailed observations were still lacking. Here we report MMS observations of an FTE-type structure in a KH wave trailing edge during KH activity on 5 May 2017 on the dawnside flank magnetopause. The structure is characterised by (1) bipolar magnetic BY variation with enhanced core field BZ and (2) enhanced total pressure with dominant magnetic pressure. The cross-section size of the FTE is found to be consistent with vortex-induced flux ropes predicted in the simulations. Unexpectedly, we observe an ion jet (VY), electron parallel heating, ion and electron density enhancements, and other signatures that can be interpreted as a reconnection exhaust at the FTE central current sheet. Moreover, pitch angle distributions of suprathermal electrons on either side of the current sheet show different properties, indicating different magnetic connectivities. This FTE-type structure may thus alternatively be interpreted as two interlaced flux tubes with reconnection at the interface as reported by Kacem et al. (2018) and Øieroset et al. (2019). The structure may be the result of interaction between two flux tubes, likely produced by multiple VIR at the KH wave trailing edge, and constitutes a new class of phenomenon induced by KH waves.

The magnetosphere of the Earth presents a large scale plasma physics laboratory in which the complex interacting plasma phenomena are involved: global convecting plasma dynamics, wave–particle interactions in the bow shock and transmitted shock waves/impulses and magnetic field reconnection in the plasma current sheets. The NASA magnetospheric multiscale mission (MMS) provides unique observations of the thin structures and wave–particles interactions at the shock-like impulses while the spacecrafts were located at the dawn terminator (the time is 2016-03-07 20:00:00 UTC). It was assumed that these impulses may be created by the interaction between the background flow and plasma clouds. It was also assumed that those clouds were produced by either flux-transfer events or by coalescence/reconnection processes at the magnetopause current layer or by the mirror instabilities inside the low latitude boundary layer. 3-D hybrid kinetic code with separate description of the background and cloud ions was used for interpretation of the observed impulse structures. In this report we will discuss the effects of particle heating and acceleration inside the foreshock of the shock-like impulses, effects of the ion and electron non-Maxwellian velocity distributions, and particle finite gyroradius, and triggering the electromagnetic instability.