  In the Earth's magnetosheath (MSH), several processes contribute to energy
dissipation and plasma heating, one of which is wave-particle interactions
between whistler waves and electrons. However, the overall impact of whistlers
on electron dynamics in the MSH remains to be quantified. We analyze 18 hours
of burst-mode measurements from the Magnetospheric Multiscale (MMS) mission,
including data from the unbiased magnetosheath campaign during February-March
2023. We present a statistical study of 34,409 whistler waves found using
automatic detection. We compare wave occurrence in the different MSH geometries
and find three times higher occurrence in the quasi-perpendicular MSH compared
to the quasi-parallel case. We also study the wave properties and find that the
waves propagate quasi-parallel to the background magnetic field, have a median
frequency of 0.2 times the electron cyclotron frequency, median amplitude of
0.03-0.06 nT (30-60 pT), and median duration of a few tens of wave periods. The
whistler waves are preferentially observed in local magnetic dips and density
peaks and are not associated with an increased temperature anisotropy. Also,
almost no whistlers are observed in regions with parallel electron plasma beta
lower than 0.1. Importantly, when estimating pitch-angle diffusion times we
find that the whistler waves cause significant pitch-angle scattering of
electrons in the MSH.
