Two-Dimensional Convective Turbulence

We show that 2D E×B ionospheric turbulence of the electron density in the equatorial electrojet is isomorphic to the viscous convection of an ordinary fluid in a porous medium due to temperature gradients. Numerical simulations reveal the strong anisotropy in the turbulence, which consists of rising hot bubbles and falling cool bubbles. These bubbles break up into fingers leading to the formation of stable shear flows. After reaching a quasisteady state, the omnidirectional energy spectrum approaches a k^-2 behavior, rather than k^-5/3 as expected from isotropic turbulence. Physical mechanisms that lead to anisotropy are analyzed.