Fast Magnetic Field Annihilation in Magnetotail Electron-scale Current Sheet | CU Experts

We present observations in Earth’s magnetotail by the Magnetospheric; Multiscale spacecraft that are consistent with magnetic field; annihilation, rather than magnetic topology change, causing fast; magnetic-to-electron energy conversion in an elongated electron-scale; current sheet. This energy conversion process is in contrast to that in; the standard electron diffusion region (EDR) of a reconnecting current; sheet where the energy of antiparallel magnetic fields is mostly; converted to electron bulk-flow energy. Fully kinetic simulation also; demonstrates that an elongated EDR is subject to the formation of; electron-scale magnetic islands in which fast energy conversion is; dominated by the annihilation. Consistent with the observations and; simulation, theoretical analysis shows that fast magnetic diffusion can; occur in an elongated EDR in the presence of nongyrotropic electron; effects. The discovery of the annihilation-dominated EDR reveals a new; form of energy conversion in the collisionless reconnection process.

Hasegawa H; Denton RE; Nakamura T; Genestreti KJ; Phan T-D; Nakamura R; Hwang K-J; Ahmadi N; Shi Q; Hesse M

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