Why isolated streamer discharges hardly exist above the breakdown field in atmospheric air

Abstract

[1] 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 photo-ionization on the discharge morphology. In previous investigations based on deterministic fluid models without background ionization, so-called double-headed streamers emerged. But in our improved model, many electron avalanches start to grow at different locations. Eventually, the avalanches collectively screen the electric field in the interior of the discharge. This happens after what we call the "ionization screening time," for which we give an analytical estimate. As this time is comparable to the streamer formation time, we conclude that isolated streamers are unlikely to exist in fields well above breakdown in atmospheric air. Citation: Sun, A. B., J. Teunissen, and U. Ebert (2013), Why isolated streamer discharges hardly exist above the breakdown field in atmospheric air, Geophys. Res. Lett., 40,

Nanosecond repetitively pulsed discharges in N2–O2mixtures: inception cloud and streamer emergence

“…Negative oxygen ions can also be a source of free electrons, where − O 2 dominates at atmospheric pressure, and the detachment field for electrons from − O 2 is similar to the breakdown field. This is how plasma builds up in regions above the breakdown field [16][17][18] which will be denoted as E c below.…”

Calculation of beams of positrons, neutrons, and protons associated with terrestrial gamma ray flashes

“…This model approximates the leader at the moment of stepping: the space stem has connected to the leader, and the full electric potential is now on the new leader tip. At this moment the leader tip "explodes" with ionization, similarly as described by Sun et al [2013], creating an inception cloud [Briels et al, 2008] and later a streamer corona. The field of the leader is tested by inserting 50 electrons with 0.1 eV energy on the symmetry axis 30 cm ahead of the leader tip, as in the work of Xu et al We also follow the approach of Xu et al [2012a] by not taking the space charge effects of the developing corona discharge into account, but only that of the stationary leader; this approximation will be justified in Figure 3 for the electrons with the highest energy.…”

The inception of pulsed discharges in air: simulations in background fields above and below breakdown

“…We remark that in the GRL [31] we were less careful with the boundary conditions and used something similar to Fig. 6.…”

“…Such situations occur for example in thunderclouds [29,30]. In our recent Geophysical Research Letter [31], we have used a 3D particle model to compare discharge formation in air at standard temperature and pressure with and without natural background ionization, in electric fields above the breakdown value. We also briefly introduced an analytic estimate for the 'ionization screening time', after which the electric field in the interior of a discharge is screened.…”

“…We also briefly introduced an analytic estimate for the 'ionization screening time', after which the electric field in the interior of a discharge is screened. In the present paper, we further elaborate on the contents of the letter [31], and focus on the distinction between background fields above and below breakdown. Therefore, we present the evolution of discharges in fields both above and below the breakdown threshold, using the same simulation model as in [31].…”