Effects of the Ionospheric Conductance on the Dynamics of the Magnetotail

We have carried out a series of numerical experiments designed to evaluate the sensitivity of global magnetohydrodynamic simulations to changes in ionospheric conductance. We multiplied the precipitating energy fluxes due to both strong pitch angle scattering and parallel currents by constant factors in the Robinson et al. (1987, https://doi.org/10.1029/JA092iA03p02565) model and used them as input to a simulated substorm interval on 14 March 2008. We also used the Kaeppler et al. (2015, https://doi.org/10.1002/2015JA021396) model. When we reduced the energy fluxes by a factor of about three (0.34), the agreement on substorm location was best. Larger conductances led to onset at later local times. For multiplication factors greater than one, the magnetotail became line tied and no flows entered the inner magnetotail region. Relatively small (