Magnetic field observations
Magnetic field observations during a cusp encounter on 23 August 2004, 10:20-10:50 UT. The left-hand figure shows TC-2 orbit across the northern cusp funnel; the Sun is to the left. The right-hand figure shows the three magnetic field components in the GSE coordinate system and the total field at bottom. The measurements are dominated by the Earth's magnetic field but during the cusp encounter one can see variations in the By component which are caused by strong electric currents existing in the cusp.