Research output: Contribution to journal › Article › peer-review
Modeling of time-evolving magnetic fields during substorms. / Lu, G; Tsyganenko, NA; Lui, ATY; Singer, HJ; Nagai, T; Kokubun, S.
In: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol. 104, No. A6, 01.06.1999, p. 12327-12337.Research output: Contribution to journal › Article › peer-review
}
TY - JOUR
T1 - Modeling of time-evolving magnetic fields during substorms
AU - Lu, G
AU - Tsyganenko, NA
AU - Lui, ATY
AU - Singer, HJ
AU - Nagai, T
AU - Kokubun, S
PY - 1999/6/1
Y1 - 1999/6/1
N2 - An attempt has been made to model the dynamics of the magnetospheric magnetic field during substorms by modifying the 1996 version of the data-based model by Tsyganenko [1996]. The modified model incorporates an adjustment to the intensity and thickness of the near-tail current sheet and a contribution from the substorm current wedge. These improvements make it possible to use the model to represent the evolution of the magnetic field during the entire substorm sequence of growth, expansion, and recovery. The modeled magnetic fields have been compared to satellite observations during three isolated substorms. According to the model results, during the substorm growth phase the thickness of the tail current sheet was gradually decreased while the intensity of the tail current was gradually increased; by the end of the growth phase a thin current sheet of 190-1340 km in half thickness was formed in a narrow region around X similar to -7.5 R-E, with a maximum westward current density of 9-23 nA/m(2). During the substorm expansion phase an eastward current associated with the substorm current wedge started to develop around X similar to -12 R-E, resulting in a collapse of the previously stretched field configuration. At the peak of an intense substorm the net tail current flow became eastward between X = -11 and X = -13 R-E, accompanied by a negative (southward) B-z tailward of -13 R-E.
AB - An attempt has been made to model the dynamics of the magnetospheric magnetic field during substorms by modifying the 1996 version of the data-based model by Tsyganenko [1996]. The modified model incorporates an adjustment to the intensity and thickness of the near-tail current sheet and a contribution from the substorm current wedge. These improvements make it possible to use the model to represent the evolution of the magnetic field during the entire substorm sequence of growth, expansion, and recovery. The modeled magnetic fields have been compared to satellite observations during three isolated substorms. According to the model results, during the substorm growth phase the thickness of the tail current sheet was gradually decreased while the intensity of the tail current was gradually increased; by the end of the growth phase a thin current sheet of 190-1340 km in half thickness was formed in a narrow region around X similar to -7.5 R-E, with a maximum westward current density of 9-23 nA/m(2). During the substorm expansion phase an eastward current associated with the substorm current wedge started to develop around X similar to -12 R-E, resulting in a collapse of the previously stretched field configuration. At the peak of an intense substorm the net tail current flow became eastward between X = -11 and X = -13 R-E, accompanied by a negative (southward) B-z tailward of -13 R-E.
KW - TAIL CURRENT SHEET
KW - GROWTH-PHASE
KW - CURRENT DISRUPTION
KW - PLASMA SHEET
KW - SYNCHRONOUS ALTITUDE
KW - CURRENT WEDGE
KW - MAGNETOTAIL
KW - MAGNETOSPHERE
KW - MODELING
KW - SUBSTORMS
U2 - 10.1029/1999JA900145
DO - 10.1029/1999JA900145
M3 - Article
VL - 104
SP - 12327
EP - 12337
JO - Journal of Geophysical Research: Biogeosciences
JF - Journal of Geophysical Research: Biogeosciences
SN - 0148-0227
IS - A6
ER -
ID: 28041114