  Simultaneous observation of characteristic 3-dimensional (3D) signatures in
the electron velocity distribution function (VDF) and intense
quasi-monochromatic waves by the Magnetospheric Multiscale (MMS) spacecraft in
the terrestrial magnetosheath are investigated. The intense wave packets are
characterised and modeled analytically as quasi-parallel circularly-polarized
whistler waves and applied to a test-particle simulation in view of gaining
insight into the signature of the wave-particle resonances in velocity space.
Both the Landau and the cyclotron resonances were evidenced in the
test-particle simulations. The location and general shape of the test-particle
signatures do account for the observations, but the finer details, such as the
symmetry of the observed signatures are not matched, indicating either the
limits of the test-particle approach, or a more fundamental physical mechanism
not yet grasped. Finally, it is shown that the energisation of the electrons in
this precise resonance case cannot be diagnosed using the moments of the
distribution function, as done with the classical ${\bf E}.{\bf J}$
"dissipation" estimate.
