Magnetic Field Annihilation in a Magnetotail Electron Diffusion Region with Electron-scale Magnetic Island Journal Article uri icon

Overview

abstract

  • 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 electron-scale current; sheet. Multi-spacecraft analysis for the magnetic field reconstruction; shows that an electron-scale magnetic island was embedded in the; observed electron diffusion region (EDR), suggesting an elongated shape; of the EDR. Evidence for the annihilation was revealed in the form of; the island growing at a rate much lower than expected for the standard; collisionless reconnection, which indicates that magnetic flux injected; into the EDR was not ejected from the X-point or accumulated in the; island, but was dissipated in the EDR. This energy conversion process is; in contrast to that in the standard 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 but transient annihilation can occur.; 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. We suggest that the; annihilation in elongated EDRs may contribute to the dissipation of; magnetic energy in a turbulent collisionless plasma.

publication date

  • February 23, 2022

has restriction

  • green

Date in CU Experts

  • March 1, 2022 7:24 AM

Full Author List

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

author count

  • 22

Other Profiles