Fully Equivalent Operational Model of SMMARC Chemistry

The impacts of nuclear weapons effect can now only be simulated through the use of very complex and computationally intensive models. This limits the ability to perform thorough engagement investigations. Attempts to reduce model run times have previously traded prediction fidelity for speed reduction by simplifying models. We propose the application of a new innovative approach to accelerate the chemistry package in the SMMARC nuclear weapon effects optical backgrounds model while preserving fidelity. The proposed approach encapsulates the input-output response behavior of the original chemistry model into a Fully Equivalent Operation Model, FEOM. The FEOM can then directly replace the original model. We anticipate the FEOM replacement in SMMARC will accelerate the chemistry predictions by a factor of 102~103, while maintaining accurate output. A proof of concept with a chemical kinetic model has demonstrated this level of acceleration. The key to this new approach in the decomposition of the model's response surface into a rapidly convergent series of low dimensional correlation functions. The FEOM will be developed by quantifying the input parameter phase space of SMMARC, and generating the individual functions comprising the FEOM. The Phase I will demonstrate the feasibility of Fully Equivalent Operational Models to significantly reduce computational times of complex models, while preserving fidelity. The SMMARC/FEOM could be incorporated directly into DSWA's ASSIST, used in DSWA-SPIET, and used independently to rapidly assess nuclear weapon effects phenomenology.