Related papers: Double-pulse streamer simulations for varying inte…
A streamer coupling theory is developed to describe the formation of homogenous emission, and the high moving speed of emission patterns in high pressure discharges. By considering the effects of both electron diffusion and electronic drift…
Streamer discharges are the primary mode of electric breakdown of air in lightning and high voltage technology. Streamer channels branch many times, which determines the developing tree-like discharge structure. Understanding these branched…
It is by now well understood that large sprite discharges at the low air densities of the mesosphere are physically similar to small streamer discharges in air at standard temperature and pressure. This similarity is based on Townsend…
The two-phase mixing layer formed between parallel gas and liquid streams is an important fundamental problem in turbulent multiphase flows. The problem is relevant to many industrial applications and natural phenomena, such as air-blast…
Standard photographs of streamer discharges show a two-dimensional projection. We here present stereo-photographic images that resolve their three-dimensional structure. We describe the stereoscopic set-up and evaluation, and we present…
We develop an axial model for single steadily propagating positive streamers in air. It uses observable parameters to estimate quantities that are difficult to measure. More specifically, for given velocity, radius, length and applied…
In this work, we aim to take a detailed experimental picture of the positive streamer. We apply optical emission spectroscopy to the first negative system (FNS, ${\rm B}^2\Sigma_{\rm u}^+\rightarrow {\rm X}^2\Sigma_{\rm g}^+$) of N$_2^+$…
Branching is an essential element of streamer discharge dynamics but today it is understood only qualitatively. The variability and irregularity observed in branched streamer trees suggest that stochastic terms are relevant for the…
We report the stereoscopic observations of two recurrent streamer waves in a single streamer structure, utilizing coordinated observations from the SOHO, STEREO, and SDO missions. Contrary to the long-held view that fast coronal mass…
In this work, we perform numerical simulations of forced two-phase isotropic turbulence to study the stationary states of a two-phase mixture. We first formulate three different approaches to force a two-phase turbulent flow that maintains…
Streamers, thin, ionized plasma channels, form the early stages of lightning discharges. Here we approach the study of extraterrestrial lightning by studying the formation and propagation of streamer discharges in various nitrogen-methane…
We present an open-source plasma fluid code for 2D, cylindrical and 3D simulations of streamer discharges, based on the Afivo framework that features adaptive mesh refinement, geometric multigrid methods for Poisson's equation, and OpenMP…
The numerical simulation of the development of a streamer discharge in a gap with an external longitudinal magnetic field was used to demonstrate the self-focusing of such discharges. Self-focusing is caused by a sharp deceleration of the…
We study negative streamers in ambient air using a 2D axisymmetric fluid model. Depending on the background electric field, we observe accelerating, steady and fading negative streamers. Fading occurs in low background fields, when negative…
The evolution of negative streamers during electric breakdown of a non-attaching gas can be described by a two-fluid model for electrons and positive ions. It consists of continuity equations for the charged particles including drift,…
We study radio emissions from positive streamers in air using 3D simulations, from which the radiated electric field is computed by solving Jefimenko's equations. The simulations are performed at 0.5 bar using two photoionization methods:…
The model of a double-well oscillator with nonlinear dissipation is studied. The self-sustained oscillations regime and the excitable one are described. The first regime consists in the coexistence of two stable limit cycles in the phase…
Nanosecond pulsed barrier discharges in atmospheric pressure argon are simulated using spatially one- and two-dimensional fluid-Poisson models using the reaction kinetics model presented by Stankov et al. [1], which considers all ten argon…
Nanosecond discharges are characterized by a shift in energy branching toward the excitation of electronic levels and dissociation, making them particularly attractive for plasma chemistry. Understanding the spatiotemporal structure of…
We investigate streamer formation in the troposphere, in electric fields above the breakdown threshold. With fully three-dimensional particle simulations, we study the combined effect of natural background ionization and of photoionization…