A novel type of turbulence, which arises in 2D electron magnetohydrodynamics, is studied by numerical simulation. Energy dissipation rates are found to be independent of the dissipation coefficients. The energy spectrum E k follows the basic Kolmogorov-type predictions, k 25͞3 for kd e . 1 and k 27͞3 for kd e , 1 (d e is the electron inertial length) and is hence independent of the linear wave properties. Results are compared with other 2D turbulent systems.

Electron magnetohydrodynamic ͑EMHD͒ turbulence is studied in two-and three-dimensional ͑2D and 3D͒ systems. Results in 2D are particularly noteworthy. Energy dissipation rates are found to be independent of the diffusion coefficients. The energy spectrum follows a k Ϫ5/3 law for kd e Ͼ1 and k Ϫ7/3 for kd e Ͻ1, which is consistent with a local spectral energy transfer independent of the linear wave properties, contrary to magnetohydrodynamic ͑MHD͒ turbulence, where the Alfvén effect dominates the transfer dynamics. In 3D spectral properties are similar to those in 2D.

Theoretical studies of collisionless reconnection in the framework of two-fluid theory are presented. In the high-β case (β≳1) reconnection is controlled by the whistler mode, leading to decoupling of ions from electrons on scales <c/ωpi. Though reconnection requires electron inertia, the reconnection rate is independent thereof, controlled only by ion inertia. Reconnection is hence much faster than in the absence of the Hall term. In the opposite limit of small β the strong axial field suppresses the whistler mode. Hence ions have to follow the electrons in the narrow reconnection layer δ∼c/ωpe, forming a macroscopic current sheet which strongly reduces the reconnection rate. Theoretical scaling laws are confirmed by numerical simulations.

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