Two-dimensional simulations of gradient-drift turbulence in the daytime equatorial electrojet

摘要: Two-dimensional numerical simulations of type II irregularities, attributed to gradient-drift instabilities, are carried out with observed profiles in the daytime equatorial electrojet. Earlier work has shown that these linearly unstable modes peak growth rates at wavelengths order 1 km. The nonlinear evolution instabilities leads saturated turbulent structures, linear drive kilometer-scale quenched by a direct energy cascade short effectively damped velocity shear and diffusion. structures show quasi-steady – 2 km horizontal waves, appear be quite isotropic plane perpendicular ambient magnetic field. electron vertical spectra, constructed from simulation output, 1–2 which qualitatively accord recent high-resolution radar observations Jicamarca Observatory Peru.