We studied the impact on global MHD simulations from different simulation initialisation methods. While the global MHD code used is GUMICS-4 we conclude that the results might be generalisable to other codes as well. It is found that different initialisation methods affect the dynamics of the Earth's space environment by creating differences in momentum transport several hours afterwards. These differences may even grow as a response to rapid solar wind condition changes.

The solar wind electric sail (E-sail) is a new way to move in the solar system efficiently without consuming propellant. The E-sail taps momentum from the solar wind by long, charged and centrifugally stretched tethers. Here we develop a new type of simulation for predicting E-sail thrust. The new simulation involves some approximations, but is robust and executes fast on a computer. The results are in good agreement with an earlier theoretical prediction. The E-sail thrust seems strong.