Unusual Plasma Formations Produced by Positive Streamers Entering the Cloud of Negatively Charged Water Droplets

Kostinskiy et al. (2015b), https://doi.org/10.1002/2015GL065620, using a high‐speed infrared (2.5–5.5 μm) camera, discovered the so‐called unusual plasma formations (UPFs) in artificial clouds of charged water droplets. UPFs had complex morphology including both streamer‐like regions and hot channel segments. They were observed both in the presence and in the absence of hot leader channels developing from the grounded plane toward the cloud. In this paper, which is aimed at revealing the genesis of UPFs, we present two UPFs that occurred inside the initial corona streamer burst of positive polarity emitted from the grounded plane, prior to the formation (or in the absence) of associated hot leader channel. These streamer bursts developed at speeds of 5–7 × 105 m/s over 1–1.5 m before entering the optically visible negatively charged cloud and producing UPFs at its periphery. Hot channel segments within UPFs were formed in very short times of the order of 1 μs or less. It is not clear if the UPFs were caused solely by the enhanced electric field near the charged cloud boundary or other factors also played a role. Occurrence of UPFs may be a necessary component of the lightning initiation process.

[1]  Yushun Zhao,et al.  Observations of the Breakthrough Phase of Attachment Process in Laboratory Long Sparks , 2022, Geophysical Research Letters.

[2]  Weijiang Chen,et al.  Separate luminous structures leading positive leader steps , 2022, Nature Communications.

[3]  Weijiang Chen,et al.  On the Step Type of Continuous Propagating Positive Leader in Laboratory‐Scale Long Spark Discharges , 2022, Geophysical Research Letters.

[4]  U. Ebert,et al.  A computational study of steady and stagnating positive streamers in N2–O2 mixtures , 2022, Plasma Sources Science and Technology.

[5]  V. Rakov,et al.  From decimeter-scale elevated ionic conductivity regions in the cloud to lightning initiation , 2021, Scientific Reports.

[6]  H. Rassoul,et al.  Insights on Space‐Leader Characteristics and Evolution in Natural Negative Cloud‐to‐Ground Lightning , 2021, Geophysical Research Letters.

[7]  U. Ebert,et al.  Simulations of positive streamers in air in different electric fields: steady motion of solitary streamer heads and the stability field , 2021, Plasma Sources Science and Technology.

[8]  Weijiang Chen,et al.  Polarity symmetry of leaders in moist air , 2021 .

[9]  V. Syssoev,et al.  Experimental Investigation of the Streamer Zone of Long‐Spark Positive Leader Using High‐Speed Photography and Microwave Probing , 2020, Journal of Geophysical Research: Atmospheres.

[10]  U. Ebert,et al.  The physics of streamer discharge phenomena , 2020, Plasma Sources Science and Technology.

[11]  V. Rakov,et al.  Numerical Simulation of Stepping and Branching Processes in Negative Lightning Leaders , 2020, Journal of Geophysical Research: Atmospheres.

[12]  F. Peeters,et al.  Implications of thermo-chemical instability on the contracted modes in CO2 microwave plasmas , 2020, Plasma Sources Science and Technology.

[13]  Y. Ju,et al.  Thermal-chemical instability of weakly ionized plasma in a reactive flow , 2019, Journal of Physics D: Applied Physics.

[14]  T. Marshall,et al.  The Mechanism of the Origin and Development of Lightning From Initiating Event to Initial Breakdown Pulses (v.2) , 2019, Journal of Geophysical Research: Atmospheres.

[15]  V. Syssoev,et al.  Abrupt Elongation (Stepping) of Negative and Positive Leaders Culminating in an Intense Corona Streamer Burst: Observations in Long Sparks and Implications for Lightning , 2018 .

[16]  V. Rakov,et al.  High-speed video observations of the fine structure of a natural negative stepped leader at close distance , 2016 .

[17]  Vladimir A. Rakov,et al.  Observations of the connection of positive and negative leaders in meter‐scale electric discharges generated by clouds of negatively charged water droplets , 2016 .

[18]  V. Rakov,et al.  Infrared images of bidirectional leaders produced by the cloud of charged water droplets , 2015 .

[19]  V. Rakov,et al.  Observation of a new class of electric discharges within artificial clouds of charged water droplets and its implication for lightning initiation within thunderclouds , 2015 .

[20]  M. Uman,et al.  Observations of corona in triggered dart‐stepped leaders , 2015 .

[21]  M. D. Tran,et al.  A negative cloud‐to‐ground flash showing a number of new and rarely observed features , 2014 .

[22]  Martin A. Uman,et al.  Negative leader step mechanisms observed in altitude triggered lightning , 2014 .

[23]  Martin A. Uman,et al.  Dart‐stepped‐leader step formation in triggered lightning , 2014 .

[24]  U. Ebert,et al.  Experimental study of the spatio-temporal development of metre-scale negative discharge in air , 2013, 1312.4765.

[25]  William H. Beasley,et al.  High‐speed video observations of a natural negative stepped leader and subsequent dart‐stepped leader , 2013 .

[26]  Ute Ebert,et al.  Experimental study on hard x-rays emitted from metre-scale negative discharges in air , 2012, 1501.00782.

[27]  Vladimir A. Rakov,et al.  Observations of stepping mechanisms in a rocket‐and‐wire triggered lightning flash , 2010 .

[28]  N. Popov.  Study of the formation and propagation of a leader channel in air , 2009 .

[29]  Martin A. Uman,et al.  High‐speed video observations of rocket‐and‐wire initiated lightning , 2009 .

[30]  N. Aleksandrov,et al.  The effect of reduced air density on streamer-to-leader transition and on properties of long positive leader , 2007 .

[31]  V. Bychkov,et al.  Thermal ionization instability of an air discharge plasma in a microwave field , 2007 .

[32]  I. A. Kossyi,et al.  Kinetic scheme of the non-equilibrium discharge in nitrogen-oxygen mixtures , 1992 .

[33]  W. Nighan.  Causes of thermal instability in externally sustained molecular discharges , 1977 .

[34]  Toshio Suzuki,et al.  Transition from the Primary Streamer to the Arc in Positive Point‐to‐Plane Corona , 1971 .

[35]  Kazuhiro Ishii,et al.  The Spark Discharge , 1947, Nature.