Fast halo currents computation in fusion reactors by electrokinetic complementary formulations

This paper presents a tool to estimate the halo current forces generated by disruptions that occurr during fusion reactors operations. The domain of the elektrokinetic problem is so complicated that two complementary formulations are used to monitor the discretization error. It turns out that thousands of cohomology generators are needed by the electric vector potential formulation, that would require an enormous amount of memory and computing power to retrieve all of them even using state-of-the-art algorithms. To solve this challenging problem, we present a novel algorithm to generate the absolute second cohomology group generators exploiting the idea of lazy cohomology generators stored as sparse vectors. The new algorithm is able to save orders of magnitude computational time.