Magnetospheric Multiscale (MMS) observations of plasma turbulence generated
by a Kelvin-Helmholtz (KH) event at the Earth's magnetopause are compared with
a high-resolution two-dimensional (2D) hybrid direct numerical simulation (DNS)
of decaying plasma turbulence driven by large-scale balanced Alfv\'enic
fluctuations. The simulation, set up with four observation-driven physical
parameters (ion and electron betas, turbulence strength, and injection scale)
exhibits a quantitative agreement on the spectral, intermittency, and
cascade-rate properties with in situ observations, despite the different
driving mechanisms. Such agreement demonstrates a certain universality of the
turbulent cascade from magnetohydrodynamic (MHD) to sub-ion scales, whose
properties are mainly determined by the selected parameters, also indicating
that the KH instability-driven turbulence has a quasi-2D nature. The validity
of the Taylor hypothesis in the sub-ion spatial range suggests that the
fluctuations at sub-ion scales have predominantly low frequencies, consistent
with a kinetic Alfv\'en wave-like nature or with quasi-static structures.
Finally, the third-order structure function analysis indicates that the cascade
rate of the turbulence generated by a KH event in the magnetopause is an order
of magnitude larger than in the ambient magnetosheath.Comment: 11 pages, 6 figures, submitted to The Astrophysical Journa