English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

A 2D approach is used to simulate the properties of positive and negativestreamers emerging from a high-voltage electrode in a long (14 cm) air gap forstandard pressure and temperature. The applied voltage varies from 100 to 500kV. To reveal the influence of photoionization, the calculations are made forvarious rates of seed electron generation in front of the streamer head. Thedifference between the properties of positive and negative streamers isassociated with the different directions of the electron drift ahead of thestreamer head. As a result, the peak electric field at the streamer head andthe streamer velocity are higher for positive voltage polarity. The averageelectric field in the negative streamer channel is approximately twice that inthe positive streamer channel, in agreement with available measurements in longair gaps. It is shown that photoionization in front of the streamer head isimportant not only for the development of strong positive discharges, but forthe development of strong negative discharges as well. An increase in thephotoionization rate increases the propagation velocity of the positivestreamer and retards the propagation of the negative streamer.

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