Tobias Keller 

Magma bodies play a critical role in Earth's geological evolution, influencing volcanic activity, crustal differentiation, and planetary-scale processes. Understanding their thermo-chemical and mechanical evolution requires models that integrate fluid dynamics, phase changes, and chemical transport. This study presents a new numerical model that couples these processes using a multi-phase, multi-component formulation. The model simulates convection, phase segregation, and thermo-chemical evolution across a wide range of scales, from crustal magma chambers to planetary magma oceans. To ensure numerical stability and physical realism, adaptive regularisation schemes are implemented, including eddy diffusivity for higher-dimensional turbulent flows and convective mixing diffusivity for one-dimensional column models. Benchmark tests confirm the accuracy of the numerical scheme, and use cases demonstrate its applicability to scenarios such as fractional crystallisation, wall-rock assimilation, and magma recharge on crustal scales, and magma ocean solidification on planetary scales. By providing an open-source implementation, this work aims to advance our understanding of dynamic magmatic systems and their role in planetary evolution.