Convection during strong driving in MHD simulations: Evolution of flux tube volume

In this work, we examine convection during very strong driving during magnetic storms using global MHD simulations of the interaction of the solar wind with the terrestrial magnetosphere. Specifically, we examine the variation of the flux tube volume along the midnight meridian using the simulation of the January 10, 1997, magnetic storm. We find that during substorm-like periods in the simulation, the flux tube volume varies significantly, rising during the growth phase and shrinking during the expansion phase. During main phase of the storm, the flux tube volume grows and remains at elevated values. We suggest that this is an important feature of convection during storms.