  We perform a Fourier space decomposition of the dynamics of non-linear
cosmological structure formation in LCDM models. From N-body simulations
involving only cold dark matter we calculate 3-dimensional non-linear density,
velocity divergence and vorticity Fourier realizations, and use these to
calculate the fully non-linear mode coupling integrals in the corresponding
fluid equations. Our approach allows for a reconstruction of the amount of mode
coupling between any two wavenumbers as a function of redshift. With our
Fourier decomposition method we identify the transfer of power from larger to
smaller scales, the stable clustering regime, the scale where vorticity becomes
important, and the suppression of the non-linear divergence power spectrum as
compared to linear theory. Our results can be used to improve and calibrate
semi-analytical structure formation models.
