3D modeling of positive streamers in air with inhomogeneous density

We study the effect of an inhomogeneous gas density on positive streamer discharges in air using a 3D fluid model with stochastic photoionization, generalizing earlier work with a 2D axisymmetric model by Starikovskiy and Aleksandrov (2019 Plasma Sources Sci. Technol. 28 095022). We consider various types of planar and (hemi)spherical gas density gradients. Streamers propagate from a region of density n0 towards a region of higher or lower gas density n1, where n0 corresponds to 300 K and 1 bar. We observe that streamers can always propagate into a region with a lower gas density. When streamers enter a region with a higher gas density, branching can occur at the density gradient, with branches growing in a flower-like pattern over the gradient surface. Depending on the gas density ratio, the gradient width and other factors, narrow branches are able to propagate into the higher-density gas. In a planar geometry, we find that such propagation is possible up to a gas density slope of 3.5n0/mm, although this value depends on a number of conditions, such as the gradient angle. Surprisingly, a higher applied voltage makes it more difficult for streamers to penetrate into the high-density region, due to an increase of the primary streamer's radius.

• View at Publisher

Full Text ( Author Manuscript , 6mb )

See Also
dataset 3D modeling of positive streamers in air with inhomogeneous density B. Guo (Baohong), U. Ebert (Ute) and H.J. Teunissen (Jannis)
techReport 3D modeling of positive streamers in air with inhomogeneous density B. Guo (Baohong), H.J. Teunissen (Jannis) and U. Ebert (Ute)
dataset 3D modeling of positive streamers in air with inhomogeneous density B. Guo (Baohong), U. Ebert (Ute) and H.J. Teunissen (Jannis)