Simulating the Extreme Storm Sudden Commencement of 4 August 1972 (Invited Presentation)

The extreme solar flares and associated Coronal Mass Ejectins (CMEs) of early August, 1972 created unique space weather conditions about the globe, culminating in the extreme storm sudden commencement late on August 4. While the events had broad impacts on human technological systems, the most notable impact was on U.S. naval mining operations towards the close of the Vietnam War. The solar activity are believed to be the source of an interplanetary shock in advance of fast coronal mass ejection. The magnetic disturbance associated with the shock likely was the cause of sudden, unintended sterilization of thousands of magnetically-triggered underwater mines deployed around Haiphong Harbor and other North Vietnamese shipping routes. Understanding this historic event is hampered by sparse solar and terrestrial observations.

This work attempts to reconstruct the solar wind conditions and magnetosphere-ionosphere response to the events leading up to and through the extreme storm sudden commencement of August 4, 1972. Satellite observations of the solar wind and magnetosheath are used to reconstruct solar wind and interplanetary magnetic field conditions directly upstream of the bow shock. These values are used to simulate the event via the Space Weather Modeling Framework (SWMF). The SWMF is configured to couple the BATS-R-US MHD model, the Rice Convection Model for the ring current, and the Ridley Ionosphere Model. The simulation results will be compared to observations to test our ability to reproduce the dynamics of the event. Model predictions of magnetic perturbations at Haiphong Harbor will be shared. The model results will be used to better understand this historic event.