Modeling of the final jump phase of a positive lightning leader

Electromagnetic fields created by the lightning leader channel in the final jump phase

The dependences between the parameters of the Lightning discharge in the leader phase and the return stroke phase are obtained. It is shown that the peak values of the electric field created by lightning are determined by the parameters of the streamer zone of the leader at the final jump phase. It is shown that a large peak value and the steepness of the lightning return stroke current are generated in the final jump phase.

Streamers, sprites, leaders, lightning: from micro- to macroscales

"Streamers, sprites, leaders, lightning: from micro- to macroscales" was the theme of a workshop in October 2007 in Leiden, The Netherlands; it brought researchers from plasma physics, electrical engineering and industry, geophysics and space physics, computational science and nonlinear dynamics together around the common topic of generation, structure and products of streamer-like electric breakdown. The present cluster issue collects relevant articles within this area; most of them were presented during the workshop. We here briefly discuss the research questions and very shortly review the …

Spontaneous emergence of space stems ahead of negative leaders in lightning and long sparks

We investigate the emergence of space stems ahead of negative leaders. These are luminous spots that appear ahead of an advancing leader mediating the leader's stepped propagation. We show that space stems start as regions of locally depleted conductivity that form in the streamers of the corona around the leader. An attachment instability enhances the electric field leading to strongly inhomogeneous, bright and locally warmer regions ahead of the leader that explain the existing observations. Since the attachment instability is only triggered by fields above 10 kV/cm and internal electric fie…

向上正闪和向下负闪先导起始的相似性

Similarities in the Initiation of Upward Positive and Downward Negative Lightning Flashes

本研究通过分析闪电先导起始过程，发现向上正闪和向下负闪的先导脉冲存在相似性，揭示了闪电起始的物理机制。

Constraints to do realistic modeling of the electric field ahead of the tip of a lightning leader

Several computer models exist to explain the observation of terrestrial gamma-ray flashes (TGFs). Some of these models estimate the electric field ahead of lightning leaders and its effects on electron acceleration and multiplication. In this paper, we derive a new set of constraints to do more realistic modeling. We determine initial conditions based on in situ measurements of electric field and vertical separation between the main charge layers of thunderclouds. A maximum electric field strength of 50 kV/cm at sea level is introduced as the upper constraint for the leader electric field. The…

Review of recent results on streamer discharges and discussion of their relevance for sprites and lightning

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 scaling with air density. First the theoretical basis of Townsend scaling and a list of six possible corrections to scaling are discussed; then the experimental evidence for the similarity between streamers and sprites is reviewed. We then discuss how far present sprite and streamer theory has been developed, and we show how streamer experiments can be interprete…