Model verses data comparison of the February 26, 2008 substorm

Development of predictive space weather models requires simulations that both run in a timely manner and are well correlated with actual observations. Results from 3D multi-fluid/multi-scale simulations of the February 26, 2008 substorm will be presented as a case study to show model vs. data comparison of the morphology and timing of a substorm. Simulation results are validated against observations from the THEMIS satellites. The simulations indicate that substorm onset is triggered by an injection of plasma into the plasma sheet with an enhanced concentration of oxygen ions. The arrival of a rotation in the IMF triggers a psuedo-breakup as it propagates past the subsolar point, initiating local and patchy reconnection in the tail. Substorm onset occurs after the enhancement in oxygen ions arrives at the plasma sheet, initiating cross-tail reconnection. The time delay between psuedo-breakup and substorm onset is approximately 35 minutes, with the substorm lasting approximately an hour. These results highlight the difficulty in determining the timing between observations of reconnection by satellites and substorm onset.