Predictability of a solar flare in May 2024 using observational data-driven MHD simulations

We examined the applicability of observational data-driven magnetohydrodynamic (MHD) simulations to flare prediction. The target event was the X1.6 flare that occurred in NOAA AR 13663 at 02:22 UT on 3 May 2024. We employed a velocity-driven model, in which the photospheric velocity field was derived from the time-series magnetograms to use as the boundary input. The simulation showed a rapid increase in both thermal and kinetic energy density around the actual onset time and location of the X1.6 flare. We revealed that the flare was triggered by two-step reconnection, in which the initial tether-cutting reconnection facilitated the subsequent breakout reconnection. We further examined whether the flare could be reproduced when the boundary input was stopped prior to the actual flare onset time, assuming the situation in which the flare must be predicted using the data before it actually occurs. When the photospheric magnetic field was fixed more than 1 h before the actual flare onset time, the flare was not reproduced in the simulations. In contrast, when the photospheric velocity field at the final observation time was incorporated to infer the subsequent magnetic evolution, the prediction lead time could be extended beyond 1 h. On the other hand, quantitative prediction of the magnitude of flares remains a subject for future study.