Our study investigates the importance of substorm-induced electric fields in accelerating ions, which eventually lead to the build-up of the ring current during geospace magnetic storms. For this purpose we use a three-dimensional dynamic ion-tracing model to calculate the particle motion. In order to produce a representative and realistic view of the ring current, a large number of test particles is required. In addition, the investigation of transport and the mechanism of energization for a wide range of initial conditions is critical aspect of our study. This simulation approach imposes high computational needs, while execution times for different initial conditions may significantly vary. Our simulation scenario is being run on a parallel platform to drastically reduce the total execution time. We also experiment with dynamic task scheduling schemes to achieve load balancing of computations and further increase performance. In this way, we are able to produce a large number of maps depicting the temporal and spatial variations of ion energy densities in the inner magnetosphere in reasonable wall-clock times. We have traced both O+ and H+ ions originating in the plasma sheet and we examine their relative influence on the ring current development. The results of the simulation show that for both ion species the inclusion of substorm-induced electric fields renders ion acceleration much more efficient.