Continuous hybrid simulations of Farley Buneman instabilities

The magnetosphere couples with the high latitude ionosphere through the earth's magnetic field lines. This coupling occurs mainly through energetic particle precipitations and electromagnetic fields. In the auroral E region, these processes cause Hall currents that drive Farley-Buneman instabilities, generating a spectrum of field-aligned plasma density irregularities. The limited data available to validate a convection model motivates the need for new validation criteria. On the other hand, fully kinetic, 3D particle-in-cell simulations of Farley-Buneman instabilities offer the most complete description of the underlying physics, including the complete treatment of collisional and dissipative processes. However, the computational cost of PIC simulation codes is tremendous, owing to the necessarily finite number of particles involved and the accompanying particle noise, making the modeling of non-local phenomena extremely challenging. An innovative solution to the problem was offered by Kovalev (2008) who developed a two-dimensional simulation of Farley-Buneman waves based on a continuous, hybrid approach.

In this poster, we propose a way to assess the mathematical and physical consistency of a convection model which relates coherent scatter spectra with electron convection. Given that the convection model doesn't contain any explicit assumption of incompressibility, we will argue that if the convection field satisfies this condition within experimental error, then the model estimates are accurate. Finally, based on Kovalev's approach, we present a new hybrid simulation of Farley-Buneman waves. We investigate phase speed saturation and examine whether the phase speeds of the waves scale with the background electric field E in the way observed by the coherent scatter radar. We also try to quantify wave turning effects, examine whether wave heating is commensurate with incoherent scatter radar observations and determine the dominant wavelength of the waves.