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Numerical simulations on the structure of plasmoids in the deep tail
Author(s) -
Hautz R.,
Scholer M.
Publication year - 1987
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl014i009p00969
Subject(s) - plasmoid , field line , physics , current sheet , magnetic reconnection , plasma sheet , magnetohydrodynamics , geophysics , plasma , mechanics , computational physics , magnetosphere , quantum mechanics
We have used a 2D resistive and compressible MHD code to study the formation and subsequent development of a plasmoid by near‐earth reconnection. The initial equilibrium configuration is characterized by a distant neutral line at a position, where the pressure in the plasma sheet has a minumum. The resistivity is allowed to grow with the current density. Reconnection at a near‐earth position is initiated by a small localized resistivity which is subsequently switched off. Fast reconnection develops self‐consistently and leads to closed field lines in the plasma sheet. Eventually the field lines to the distant neutral line are reconnected and the pinched‐off plasma sheet moves downtail. Continuous reconnection leads to a layer of reconnected field lines around the plasmoid which are connected to interplanetary field lines. In the case of open top and bottom boundaries secondary tearing leads to two near‐earth neutral lines and the subsequent evolution of a second plasmoid. This can result in the figure‐8 structure inferred from magnetic field data in the deep tail. A closed high latitude boundary inhibits the secondary tearing and the original plasmoid is more elongated as it is ejected down the tail.