Density models for streamer discharges: Beyond cylindrical symmetry and homogeneous media

Density models for streamer discharges: Beyond cylindrical symmetry and homogeneous media

Streamer electrical discharges are often investigated with computer simulations of density models (also called reaction-drift-diffusion models). We review these models, detailing their physical foundations, their range of validity and the most relevant numerical algorithms employed in solving them.We focus particularly on schemes of adaptive refinement, used to resolve the multiple length scale...

Spatially hybrid computations for streamer discharges : II. Fully 3D simulations

We recently have presented first physical predictions of a spatially hybrid model that follows the evolution of a negative streamer discharge in full three spatial dimensions; our spatially hybrid model couples a particle model in the high field region ahead of the streamer with a fluid model in the streamer interior where electron densities are high and fields are low. Therefore the model is c...

High-order fluid model for streamer discharges: II

The high-order fluid model developed in part I of this series is employed here to study the propagation of negative planar streamer fronts in pure nitrogen. The model consists of the balance equations for electron density, average electron velocity, average electron energy and average electron energy flux. These balance equations have been obtained as velocity moments of Boltzmann’s equation an...

Electron density fluctuations accelerate the branching of positive streamer discharges in air.

Branching is an essential element of streamer discharge dynamics. We review the current state of theoretical understanding and recall that branching requires a finite perturbation. We argue that, in current laboratory experiments in ambient or artificial air, these perturbations can only be inherited from the initial state, or they can be due to intrinsic electron-density fluctuations owing to ...

Production of runaway electrons by negative streamer discharges