Evidence for electron acceleration up to ∼300 keV in the magnetic reconnection diffusion region of Earth's magnetotail -: art. no. 195001

We report direct measurements of high-energy particles in a rare crossing of the diffusion region in Earth's magnetotail by the Wind spacecraft. The fluxes of energetic electrons up to similar to300 keV peak near the center of the diffusion region and decrease monotonically away from this region. The diffusion region electron flux spectrum obeys a power law with an index of -3.8 above similar to2 keV, and the electron angular distribution displays strong field-aligned bidirectional anisotropy at energies below similar to2 keV, becoming isotropic above similar to6 keV. These observations indicate significant electron acceleration inside the diffusion region. Ions show no such energization.