A robust and conservative dynamical low-rank algorithm

Dynamical low-rank approximation, as has been demonstrated recently, can be extremely efficient in solving kinetic equations. However, a major deficiency is that they do not preserve the structure of underlying physical problem. For example, classic dynamical methods violate mass, momentum, and energy conservation. In [L. Einkemmer, I. Joseph, J. Comput. Phys. 443:110495, 2021] conservative approach proposed. directly integrating resulting equations motion, similar to approach, results an ill-posed scheme. this work we propose robust, i.e. well-posed, integrator for conserves mass momentum (up machine precision) significantly improves We also report improved qualitative some problems show how combined with rank adaptive