Dynamics of the Earth's Magnetotail in Substorms: Impact of Kinetic Effects

There are two current systems essential for substorms. In the ionosphere, one system has a current closure in the east-west direction while the other has a north-south current closure. The latter requires a dynamo in the magnetotail. A model with a kinetic instability known as the cross-field current instability generates both substorm current systems simultaneously. Supporting evidence for this process is found from in situ magnetotail measurements.