  The role of large amplitude whistler waves in the energization and scattering
of solar wind electrons has long been an interesting problem in Space Physics.
To study this wave-particle interaction, we developed a vectorized test
particle simulation with a variational calculation of the Lyapunov exponents.
From using secular perturbation theory on this Hamiltonian system of wave and
particle, we confirmed that the pitch angle diffusion of the particle was along
the constant Hamiltonian surface and that it was driven by the interaction with
the resonance surfaces. We also showed that oblique whistlers could efficiently
scatter field-aligned strahl electrons into the halo population in the solar
wind. We demonstrated through simulation that these waves were capable of
generating horn-like features in the velocity distribution function, similar to
recent PIC simulation results in the literature.
