Probing background ionization: positive streamers with varying pulse repetition rate and with a radioactive admixture

  title={Probing background ionization: positive streamers with varying pulse repetition rate and with a radioactive admixture},
  author={Sander Nijdam and Gideon Wormeester and Eddie van Veldhuizen and Ute Ebert},
  journal={Journal of Physics D: Applied Physics},
Positive streamers need a source of free electrons ahead of them to propagate. A streamer can supply these electrons by itself through photo-ionization, or the electrons can be present due to external background ionization. Here we investigate the effects of background ionization on streamer propagation and morphology by changing the gas composition and the repetition rate of the voltage pulses, and by adding a small amount of radioactive 85Kr. We find that the general morphology of a positive… 

Double pulse streamer experiments

Summary form only given. It is well known that streamer discharges are influenced by background ionization and other effects of previous discharges1. Also externally applied background ionization can

The influence of bremsstrahlung on electric discharge streamers in N2, O2 gas mixtures

Streamers are ionization filaments of electric gas discharges. Negative polarity streamers propagate primarily through electron impact ionization, whereas positive streamers in air develop through

How pulse polarity and photoionization control streamer discharge development in long air gaps

A 2D approach is used to simulate the properties of positive and negative streamers emerging from a high-voltage electrode in a long (14 cm) air gap for standard pressure and temperature. The applied

Investigation of positive streamers by double-pulse experiments, effects of repetition rate and gas mixture

Streamer discharges are often operated in a repetitively pulsed mode and are therefore influenced by species left over from the previous discharge, especially free electrons and ions. We have

Positive double-pulse streamers

Residual charges and species created by previous streamers have a great impact on the characteristics of the next discharge. This is especially pronounced in repetitively pulsed discharges, where the

The structure of ionization showers in air generated by electrons with 1 MeV energy or less

Ionization showers are created in the Earth's atmosphere by cosmic particles or by run-away electrons from pulsed discharges or by the decay of radioactive elements like radon and krypton. These

Guided ionization waves: The physics of repeatability

Free to read on publisher website Guided ionization waves, or plasma streamers, are increasingly important for many applications in spanning materials processing and biomedicine. The highly

Positive double-pulse streamers: how pulse-to-pulse delay influences initiation and propagation of subsequent discharges

Residual charges and species created by previous streamers have a great impact on the characteristics of the next discharge. This is especially pronounced in repetitively pulsed discharges, where the

Streamer properties and associated x-rays in perturbed air

Streamers are ionization waves in electric discharges. One of the key ingredients of streamer propagation is an ambient gas that serves as a source of free electrons. Here, we explore the dependence

The role of free electrons in the guiding of positive streamers

Because positive streamers propagate opposite to the electron drift velocity, their growth not only depends on the local electric field, but also on the electron density ahead of them. We have



Probing photo-ionization: simulations of positive streamers in varying N2 : O2-mixtures

Photo-ionization is the accepted mechanism for the propagation of positive streamers in air though the parameters are not very well known; the efficiency of this mechanism largely depends on the

Probing photo-ionization: experiments on positive streamers in pure gases and mixtures

Positive streamers are thought to propagate by photo-ionization; the parameters of photo-ionization depend on the nitrogen : oxygen ratio. Therefore we study streamers in nitrogen with 20%, 0.2% and

Controlling branching in streamer discharge by laser background ionization

Irradiation with a KrF laser controlled the positive streamer branching in atmospheric argon gas. This laser irradiation changed the amount of background ionization before the streamer discharge.

Role of electronegative gas admixtures in streamer start, propagation and branching phenomena

A critical analysis of photoionization as the major process for seed electron production ahead of the cathode-directed streamer has been made. The accumulation of ions between pulses and fast

Effect of preionization, fluorine concentration, and current density on the discharge uniformity in F2 excimer laser gas mixtures

The discharge homogeneity in F2-based excimer laser gas mixtures and its dependence on various key parameters, such as the degree of preionization, preionization delay time, F2 concentration and

A pr 2 00 8 Positive and negative streamers in ambient air : modeling evolution and velocities

We simulate short positive and negative streamers in air at standard temperature and pressure. They evolve in homogeneous electric fields or emerge from needle electrodes with voltages of 10 to 20

Circuit dependence of the diameter of pulsed positive streamers in air

The diameter and branching structure of positive streamers in ambient air are investigated with a fast iCCD camera. We use different pulsed power circuits and find that they generate different

Formation and structure of primary and secondary streamers in positive pulsed corona discharge—effect of oxygen concentration and applied voltage

Primary and secondary streamers of positive pulsed corona discharge are observed in a point-to-plane gap using a short-gated intensified CCD camera in an air-like environment. The influences of

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

  • A. LuqueU. Ebert
  • Physics
    Physical review. E, Statistical, nonlinear, and soft matter physics
  • 2011
The intrinsic stochastic particle noise triggers branching of positive streamers in air at atmospheric pressure, and it is concluded that the ratio of branching length to streamer diameter agrees within a factor of 2 with experimental measurements.

Production of runaway electrons by negative streamer discharges

[1] In this paper we estimate the probability that cold electrons can be accelerated by an ambient electric field into the runaway regime, and discuss the implications for negative streamer