This proposal seeks to develop a fundamental mechanism-based understanding of the mechanics of ferromagnetic shape memory alloys under high pressures and short time scales. Extreme conditions i.e., large stresses, pressures and strain rates, cause these materials to release large coupled energy densities. This multi-functionality originates at microscopic scales, and is governed by the evolution of solid-solid phase transformations. However, the kinetics of these phase transformations are poorly understood at extreme pressures and strain rates, limiting predictive material design tools. The proposed research programme will result in unique experimental infrastructure and multi-scale data sets to fill these knowledge gaps. A high throughput laser-driven shock compression experiment will be developed with in-situ high-speed optical instrumentation and microscopy. This setup will be integrated with a home-built multi-physics platform to apply (quasi-)static magnetic fields in-situ. Using this unique experimental capability, my team will build multi-scale data sets on the multi-physical response of single crystal Ni-Mn-Ga (chosen as a model material) at high pressures (>10 GPa) and strain rates (order of 10^6/s). These data sets, in combination with uniaxial data at comparable strain rates (performed using miniature Kolsky bar experiments), will allow us to de-couple the effects of pressure on the multi-physical macroscopic response and micro-structure evolution in single crystal Ni-Mn-Ga. Analysis of these large multi-dimensional data sets will be performed using a hybrid computational code developed within a multi-scale continuum modeling framework to discover the kinetic laws that govern phase boundary kinetics under complex stress states, high pressures, and short time scales. This fundamental understanding will aid the design and synthesis of ferromagnetic devices for impact absorption, pulsed power generation and solid-state heat pumping.