## Section: Software

Keywords : Vlasov, Particle In Cell, Unstructured Grid, finite elements, parallelization.

### SPIN

Participants : Sébastien Jund, Guillaume Latu [ correspondant ] , Pierre Navaro, Eric Sonnendrücker.

The Scalable Particle-IN-cell (Spin) code is dedicated to the solving of Vlasov-Maxwell equations, using finite elements for the Maxwell solver. This code is designed to be able to scale well on parallel machines. We have elaborated different strategies to balance both the computational loads of the Vlasov part (Particle In Cell method) and the Maxwell part (Edge finite elements). In order to do that we take into account the number of particles and elements per processor. This code has run several 2D test cases, and we are working now on a 3D version.

The Maxwell solver can handle hybrid grids (triangles and quadrangles) and has the capability of using high order elements. We built the numerical scheme in order to achieve a charge conserving property. Another characteristic of the solver concerns parallel work distribution. The computations on quadrangles are highly parallel: there are few communications and nearly no dependencies between computations. On the triangles, we use a sparse solver in order to solve Maxwell equation (all triangles are tightly coupled). The PASTIX solver (INRIA/Scalapplix team) or a classical Conjugate Gradient solver are used in order to perform the sparse computations.