Generation of field-aligned current (FAC) and convection through the formation of pressure regimes: Correction for the concept of Dungey's convection

T. Tanaka, Masakazu Watanabe, M. Den, S. Fujita, Y. Ebihara, T. Kikuchi, K. K. Hashimoto, R. Kataoka

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

In this paper, we try to elucidate the generation mechanism of the field-aligned current (FAC) and coexisting convection. From the comparison between the theoretical prediction and the state of numerical solution from the high-resolution global simulation, we obtain the following conclusions about the distribution of dynamo, the magnetic field structure along the flow path that diverges Poynting flux, and energy conversion promoting the generation of electromagnetic energy. The dynamo for the region 1 FAC, which is in the high-latitude-side cusp-mantle region, has a structure in which magnetic field is compressed along the convection path by the slow mode motion. The dynamo for the region 2 FAC is in the ring current region at the inner edge of the plasma sheet, and has a structure in which magnetic field is curved outward along the convection path. Under these structures, electromagnetic energy is generated from the work done by pressure gradient force, in both dynamos for the region 1 and region 2 FACs. In these generation processes of the FACs, the excitation of convection and the formation of pressure regimes occur as interdependent processes. This structure leads to a modification in the way of understanding the Dungey's convection. Generation of the FAC through the formation of pressure regimes is essential even for the case of substorm onset.

Original languageEnglish
Pages (from-to)8695-8711
Number of pages17
JournalJournal of Geophysical Research: Space Physics
Volume121
Issue number9
DOIs
Publication statusPublished - Sep 1 2016

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field aligned currents
convection
magnetic fields
Magnetic fields
Electromagnetic waves
magnetic field
DC generators
electromagnetism
rotating generators
energy conversion
ring currents
energy
Pressure gradient
cusps
pressure gradients
Energy conversion
current ring
polar regions
Earth mantle
pressure gradient

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Cite this

Generation of field-aligned current (FAC) and convection through the formation of pressure regimes : Correction for the concept of Dungey's convection. / Tanaka, T.; Watanabe, Masakazu; Den, M.; Fujita, S.; Ebihara, Y.; Kikuchi, T.; Hashimoto, K. K.; Kataoka, R.

In: Journal of Geophysical Research: Space Physics, Vol. 121, No. 9, 01.09.2016, p. 8695-8711.

Research output: Contribution to journalArticle

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