The project funded by the ERC grant will use a mathematical theory known as optimal control. In some astrophysical objects, the generation of magnetic fields crucially depends on initial conditions. Mathematically, this means that the non-linear equations governing their evolution can have multiple solutions, and that depending on the initial magnetic perturbation, the system will spontaneously evolve towards one equilibrium rather than another: for example a dynamo solution, i.e. the object will develop a persistent, self-sustaining magnetic field, or conversely a non-magnetic solution.

Identifying a dynamo equilibrium directly is very difficult, due to the nature of these equations, and often requires a fairly precise idea of the solution sought... which we don't have! Optimal control theory allows us to get round this obstacle, as we showed in a recent article in the journal PRL (Physical Review Letters): we look for the initial perturbations that maximize the energy of the magnetic field at a given time, then using classical numerical simulation, **we check a posteriori that these "initial seeds" are capable of triggering a dynamo instability, and we follow their evolution until we reach the desired equilibrium. **However, it may not work every time... that's the risky part of the project!