Plasmoid formation and evolution in a numerical simulation of a substorm

Plasmoids are thought to occur as a consequence of the formation of a near-Earth neutral line during the evolution of a geomagnetic substorm. Using a 3D, global MHD simulation of the interaction of the Earth's magnetosphere with the solar wind, we initiate a substorm by a southward turning of the Interplanetary Magnetic Field (IMF) after a long period of steady northward field. A large plasmoid is formed and ejected. We show field line maps of its shape and relate its formation time to the progress of the substorm as indicated by the cross polar potential. Because of the large region of closed field in the magnetotail at the time of the substorm, this plasmoid is longer in axial dimension than is typically observed. We compare the simulation results with the type of satellite observations which have been used to argue for the existence of plasmoids or of traveling compression regions (TCRs) in the lobes or magnetosheath. The simulation predicts that plasmoid passage would result in a strong signal in the cross tail electric field.

[1]  T. Sanderson,et al.  CDAW 8 observations of plasmoid signatures in the geomagnetic tail: An assessment , 1989 .

[2]  E. W. Hones,et al.  On the three-dimensional magnetic structure of the plasmoid created in the magnetotail at substorm onset , 1982 .

[3]  Robert L. McPherron,et al.  Satellite studies of magnetospheric substorms on August 15, 1968. IX - Phenomenological model for substorms. , 1973 .

[4]  J. Birn,et al.  Plasmoid evolution in an extended magnetotail , 1991 .

[5]  E. W. Hones,et al.  Three‐dimensional computer modeling of dynamic reconnection in the geomagnetic tail , 1981 .

[6]  R. Anderson,et al.  Average plasma and magnetic field variations in the distant magnetotail associated with near-Earth substorm effects , 1987 .

[7]  W. Hughes,et al.  Geomagnetic substorm association of plasmoids , 1993 .

[8]  D. Baker,et al.  IMP-8 observations of traveling compression regions: New evidence for near-Earth plasmoids and neutral lines , 1990 .

[9]  E. W. Hones,et al.  Substorm associated traveling compression regions in the distant tail: Isee‐3 Geotail observations , 1984 .

[10]  J. Lyon,et al.  The solar wind-magnetosphere-ionosphere current-voltage relationship , 1987 .

[11]  E. W. Hones.  Magnetotail: its generation and dissipation , 1976 .

[12]  W. Hughes,et al.  Observations of earthward and tailward propagating flux rope plasmoids: Expanding the plasmoid model of geomagnetic substorms , 1994 .

[13]  J. Birn,et al.  Parallel electric fields in a simulation of magnetotail reconnection and plasmoid evolution , 2013 .

[14]  B. Klecker,et al.  Characteristics of plasmoidlike structures in the distant magnetotail , 1984 .

[15]  E. W. Hones,et al.  ISEE 3 observations of traveling compression regions in the Earth`s magnetotail , 1993 .

[16]  E. W. Hones,et al.  Plasmoid-associated energetic ion bursts in the deep geomagnetic tail: Properties of plasmoids and the postplasmoid plasma sheet , 1987 .

[17]  D. Baker,et al.  ISEE 3 plasmoid and TCR observations during an extended interval of substorm activity , 1992 .

[18]  W. Hughes,et al.  On the formation and evolution of plasmoids: A survey of ISEE 3 geotail data , 1992 .

[19]  R. Walker,et al.  Magnetic flux ropes in 3-dimensional MHD simulations , 1990 .