Slide 15Click the figures to make them larger
Slide 15
Pressure (Pa) in the Y=0 plane in the near-Earth tail at 2h 21 min (after 20 minutes of northward turning of IMF Bz).
Slide 16Y-directed current density jy (A/m2) in the Y=0 plane in the near-Earth tail at 2h 21 min (after 20 minutes of northward turning of IMF Bz).
Slide 17Field lines (green, yellow), streamlines (blue) and rainbow coded pressure (limited by 0.1 nPa) in the Y=0 plane after approximately 1 hour of zero IMF. Notice the plasmoid signature in the tail at about X = -55 RE.
Slide 18X-directed current (jx) at X=-4 plane. Red is sunward and blue is antisunward current. The second innermost red circle has radius 3.7 R_E, which is the radius of the inner boundary of the MHD equations. The innermost circle has radius 1 R_E. On the left and right the ring current is seen; on the eveningside (right) it is positive (sunward) and on the morningside (left) it is negative (antisunward). The simulation produces the ring current at too far distance from the Eart (almost 8 R_E at equatorial plane). The smaller scale currents near the origin are part of a substorm current wedge (SCW). The total current flowing in the wedge is about 25 kA, which is rather small figure.
Slide 19Ionospheric situation at the time of the previous slide, where a trace of the SCW was seen in the magnetosphere. In the ionospheric plane the SCW is seen near the midnight at the lower part of the figure. A rough estimate of the total current flowing in the wedge: the current intensity at the wedge is about 0.1 uA/m2 (u=micro) and the dimensions of the wedge region are about 500 x 500 km, thus the total current is about 25 kA which agrees with the magnetospheric estimate. The Region-1 current which at this moment is enhancing from the dayside because IMF Bz has again turned southward is little bit more intense and distributed over a much wider area, thus its total magnitude is clearly larger.