An Expert Analysis of Magnetohydrodynamic Propulsion and its Applications Part I: Foundational Principles of Magnetohydrodynamics (MHD) 1.1. Defining the Field: From Theory to ApplicationMagnetohydrodynamics (MHD), also known as magneto-fluid dynamics or hydromagnetics, is a professional field that exists at the intersection of physics, engineering, and fluid mechanics.1 It is a model used to describe the dynamics of electrically conducting fluids in the presence of electromagnetic fields.3 The fluids can be ionized gases (plasma), liquid metals, or even electrolytes like seawater, with MHD treating all interpenetrating particle species as a single, continuous medium.1 This discipline is essential for understanding phenomena as diverse as solar flares, the Earth's magnetosphere, fusion energy devices, and certain forms of propulsion.3The theoretical underpinning of MHD is a complex system of coupled, nonlinear partial differential equations.2 These equations describe the conservat...