Relationship between sprite streamer behavior and lightning‐driven electric fields

Abstract

[1] The lightning-driven electric fields not only initiate sprite streamers at high altitudes but also control their propagation to lower altitudes until termination. Thus, the relationship between sprite streamer behavior and their causative lightning-driven ambient electric field can reveal the internal microphysics during sprite development. In this work, we combined the measurements of broadband electromagnetic radiation from sprite-producing lightning, high-speed video of sprite optical emissions acquired at 5,000-10,000 frames per second, and numerical simulations to infer the background lightning-driven electric fields during the full extent of downward streamer propagation. For four sprites analyzed, all with positive polarity downward streamers, the observed streamers all terminate at locations where the ambient electric field is approximately 0.05 E k , independent of the altitude where this field is reached. For two sprites with significant horizontal extent, the points of streamer termination closely follow the spatial contour of the E = 0.05 E k surface, further confirming the consistency of this termination background field for positive sprite streamers. The positive streamers also begin their significant deceleration where the background field drops below 0.12-0.24 E k . These measured termination field (E ter ) and deceleration field (E dec ) are consistent with previous laboratory experiments of positive streamer stopping field and critical field to sustain stable propagation. These results connect sprite streamer behavior with the lightning-driven background electric fields and can be a step to further constrain the existing model of streamer propagation in the mesosphere.Citation: Li, J., and S. Cummer (2012), Relationship between sprite streamer behavior and lightning-driven electric fields,

High-Speed Observations of Sprite Streamers

“…A similar analysis has also been presented by Gordillo-Vázquez (2008. However, it is now clear that the glow is more likely caused by electric fields associated with negative charge accumulating in the streamer channel (Luque and Ebert 2010;Liu 2010;Li and Cummer 2012;Qin et al 2012;Kosar et al 2012).…”

“…The explanation for downward only at onset has been sought in the formation of screening charges (polarization) in the halo or at the bottom of the sharply increasing background electron density profile, where the streamer onset is likely to occur. This polarization will screen the driving electric field above the onset altitude, thus effectively preventing the upward propagating streamer from forming (Qin et al 2011(Qin et al , 2012Li and Cummer 2012;Luque and Ebert 2010). Another possibility has been presented by Liu et al (2012) and Kosar et al (2012).…”

“…Modeling has successfully reproduced most sprite features observed, allowing a detailed evaluation of the processes involved. Recently, Luque and Ebert (2009), Qin et al (2011), Li and Cummer (2012) and Luque and Gordillo-Vázquez (2012) have presented modeling efforts placing streamer formation as part of the larger response of the mesosphere to an electric pulse caused by a cloud-to-ground lightning discharge, and modeling efforts are under way by several groups to relate the lightening pulse shape and charge transport, inferred from electric and magnetic observations, to actual sprite features observed optically with highspeed imagers. Also the potential impact on the global electric circuit is being investigated (Rycroft and Odzimek 2010).…”

Three years of lightning impulse charge moment change measurements in the United States

“…Lightning charge moment change measurements using remote magnetic field measurements and our basic approach, albeit with more complex processing, have been validated previously [ Ross et al , ] by separately analyzing electric and magnetic field measurements. We have anecdotally compared measurements from the CMCN system to those obtained with more complex processing of data from the magnetic field coils used in previous studies [ Cummer and Inan , ; Li and Cummer , ] and found good agreement.…”

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

“…We consider the inception of pulsed discharges in homogeneous background fields, far from electrodes or other charge accumulations. 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.…”