E. P. Alves, T. Grismayer, R. Fonseca, L. O. Silva
Recent particle-in-cell (PIC) simulations of the Kelvin-Helmholtz instability have revealed the emergence of a strong and large-scale DC magnetic field component at the shear interface, which is not captured by the standard linear two-fluid theory. We show that the DC magnetic field results from electron mixing across the shear interface. The mixing mechanism can be modeled by a an electron thermal expansion across the shear, in a warm shear scenario, and we connect this picture to the cold shear scenario where the development of the standard cold fluid KHI produces an effective average temperature that drives the expansion. We outline a simple analytical model that describes the growth and saturation level of the DC magnetic field.
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http://arxiv.org/abs/1205.2293
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