Magnetic reconnection occurs in turbulent plasmas like shock transition regions, while its exact role in energy dissipation therein is not yet clear. We perform a 2D particle-in-cell simulation for foreshock waves and study electron heating associated with reconnection. The probability distribution of Te exhibits a shift to higher values near reconnection X-lines compared to elsewhere. By examining the Te evolution using the superposed epoch analysis, we find that Te is higher in reconnection than in non-reconnecting current sheets, and Te increases over the ion cyclotron time scale. The heating rate of Te is 10%-40% miVA2, where VA is the average ion Alfvén speed in reconnection regions, which demonstrates the importance of reconnection in heating electrons. We further investigate the bulk electron energization mechanisms by decomposing under guiding center approximations. Around the reconnection onset, E|| dominates the total energization partly contributed by electron holes, and the perpendicular energization is dominant by the magnetization term associated with the gyro-motion in the inhomogeneous fields. The Fermi mechanism contributes negative energization at early time mainly due to the Hall effect, and later the outflow in the reconnection plane contributes more dominant positive values. After a couple of ion cyclotron periods from reconnection onset, the Fermi mechanism dominates the energization. A critical factor for initiating reconnection is to drive current sheets to the de-scale thickness. The reconnection structures can be complicated due to flows originated from the ion-scale waves, and interactions between multiple reconnection sites. These features may assist future analysis of observation data.

The 1-Hz whistler wave precursor attached to shock-like structures are often observed in foreshock. Using observations from the Magnetospheric Multiscale mission, we investigate the interactions between 1-Hz waves and ions. Incoming solar wind ions do not gyro-resonate with the wave, since typically the wave is right-handed in their frame. We demonstrate that solar wind ions commonly exhibit 180 gyro-phase bunching from the wave magnetic field, understanding it with a reconciled linear picture for non-resonant ions and non-linear trapping theory of anomalous resonance. Along the longitudinal direction, solar wind ions experience Landau resonance, exhibiting either modulations at small wave potentials or trapping in phase-space holes at large potentials. The results also improve our understanding of foreshock structure evolution and 1-Hz wave excitation. Shock-like structures start with having incoming solar wind and remotely-reflected ions from further downstream. The ion-scale 1-Hz waves can already appear during this stage. The excitation may be due to shock-like dispersive radiation or kinetic instabilities resonant with these remotely-reflected ions. Ions reflected by local shock-like structures occur later, so they are not always necessary for generating 1-Hz waves. The wave leads to ion reflection further upstream, which may cause reformation. In one event, locally-reflected ions exhibit anomalous resonance in the early stage, and later approach to the gyro-resonant condition with gyro-phases ~270 . The latter is possibly due to nonlinear trapping in regions with an upstream-pointing magnetic field gradient, linked to reformation. Some additional special features like frequency dispersions are observed, requiring better explanations in the future.

We investigate electrostatic waves in a magnetopause reconnection diffusion region event. In the electron diffusion region on the magnetospheric side, an oblique electrostatic wave is observed. The local distribution exhibits fast non-gyrotropic electron beams with drifts comparable to the electron thermal speed, but the wave has a much lower phase speed. Response of ions and possible cold electrons may contribute to wave excitation. Near the current sheet mid-plane, parallel electron beam-mode waves are modulated by whistler waves. In the separatrix region, parallel waves associated with field-aligned electron beams and perpendicular electron cyclotron waves with loss cone distributions exhibit modulation frequencies in the lower-hybrid wave frequency range. We infer that lower-hybrid waves scatter electrons to produce beams and alter loss cones to modulate electrostatic waves. The results advance our understanding about the regimes and mechanisms of electrostatic waves in reconnection and their coupling with lower-frequency waves.