Evolution of IMF By induced asymmetries during substorms: Superposed epoch analysis at geosynchronous orbit

The B y component of the magnetic field inside magnetosphere is positively correlated with Interplanetary Magnetic Field (IMF). This leads to asymmetries in aurora, plasma convection and electric currents between northern southern hemispheres It has been demonstrated that conjugate locations ionosphere become less displaced during magnetospheric substorms, which are associated enhanced reconnection near-Earth tail. Here we directly address how average magnetotail evolves relative substorm onset by performing a superposed epoch analysis observed at nightside geosynchronous orbit periods dominant IMF . observations demonstrate | increases loading phase prior onset. maximizes expansion subsequently reduced remaining unloading phase. trends more pronounced using lists on identify stronger substorms. Since dayside dominates over tail phase, whereas results build up low agreement previous case studies auroral features.