Authors: Peter W. Schuck (NASA/GSFC), Mark G. Linton (NRL), and James E. Leake (NASA/GSFC)

Understanding the evolution of electric currents in the solar corona is key to almost all the fundamental questions in solar physics such as those associated with reconnection, flares, coronal mass ejections (CMEs), coronal heating, and the emergence of the ARs that are the origin of the major disruptive space weather events. In the famous Melrose-Parker debate, Melrose argued that the corona can support bare currents whereas Parker argued that all bare current systems are locally dressed with sheath currents. The neutralizing scale of the coronal sheath current is highly controversial and so are its implications for forces driving solar eruptions. Using state-of-the-art numerical simulations of flux rope emergence combined with cutting edge magnetic field analysis we describe the birth of an active region as its sheath current crosses the photosphere.