by Holger Isenberg » Thu Sep 15, 2022 11:52 pm
Found the original research. It only talks about propagation of ionization waves, not actual objects. But the interesting observation detail is the acceleration of the propagation. Why would a purely visual wave accelerate, i.e. start slow? That acceleration, i.e. some inertia preventing the immediate final velocity start, appears to be more a hint to moving matter.
High-Speed Observations of Sprite Streamers
H. C. Stenbaek-Nielsen, T. Kanmae, M. G. McHarg & R. Haaland
Surveys in Geophysics volume 34, pages 769–795 (2013)
Open Access, Published: 15 March 2013
https://link.springer.com/article/10.10 ... 013-9224-4
The observation that sprites start with a downward streamer was somewhat unexpected as models, for example Liu and Pasko (2004), predicted streamer formation with both a downward (positive) streamer propagating in the direction of the causal electric field, and simultaneously, an upward propagating (negative) streamer, so-called double-headed streamers.
Because of the rapid descent, the optical structure in the halo cannot represent features in the background atmosphere. We note that we have a number of other examples with significantly faster downward motion. While the main halo luminosity fades, the structure in the halo continues and eventually spawns a streamer which descends at 1.7 × 10E7 m/s. The streamer clearly forms after the main halo has faded, and it may be that the structure is actually the ionization wave proposed by Luque and Ebert (2009).
The velocity of sprite streamers is typically in the 10E6–10E8 m/s range (Stanley et al. 1999; Moudry et al. 2003; McHarg et al. 2002, 2007; Cummer et al. 2006). Upward streamers are generally slightly faster; the highest velocity we have observed is 1.4 × 10E8 m/s (almost half the velocity of light) (McHarg et al. 2002). As seen in Figs. 3, 5, and 6, the downward streamers accelerate after formation. Eventually, the streamers reach a maximum velocity after which they slow down and eventually fade at lower altitude. McHarg et al. (2007) find acceleration and deceleration values in the 10E5–10E10 m/s^2 range.
[edited: fixed the exp-numbers]
Found the original research. It only talks about propagation of ionization waves, not actual objects. But the interesting observation detail is the acceleration of the propagation. Why would a purely visual wave accelerate, i.e. start slow? That acceleration, i.e. some inertia preventing the immediate final velocity start, appears to be more a hint to moving matter.
High-Speed Observations of Sprite Streamers
H. C. Stenbaek-Nielsen, T. Kanmae, M. G. McHarg & R. Haaland
Surveys in Geophysics volume 34, pages 769–795 (2013)
Open Access, Published: 15 March 2013
https://link.springer.com/article/10.1007/s10712-013-9224-4
[quote]The observation that sprites start with a downward streamer was somewhat unexpected as models, for example Liu and Pasko (2004), predicted streamer formation with both a downward (positive) streamer propagating in the direction of the causal electric field, and simultaneously, an upward propagating (negative) streamer, so-called double-headed streamers.
[/quote]
[quote]Because of the rapid descent, the optical structure in the halo cannot represent features in the background atmosphere. We note that we have a number of other examples with significantly faster downward motion. While the main halo luminosity fades, the structure in the halo continues and eventually spawns a streamer which descends at 1.7 × 10E7 m/s. The streamer clearly forms after the main halo has faded, and it may be that the structure is actually the ionization wave proposed by Luque and Ebert (2009).[/quote]
[quote]The velocity of sprite streamers is typically in the 10E6–10E8 m/s range (Stanley et al. 1999; Moudry et al. 2003; McHarg et al. 2002, 2007; Cummer et al. 2006). Upward streamers are generally slightly faster; the highest velocity we have observed is 1.4 × 10E8 m/s (almost half the velocity of light) (McHarg et al. 2002). As seen in Figs. 3, 5, and 6, the downward streamers accelerate after formation. Eventually, the streamers reach a maximum velocity after which they slow down and eventually fade at lower altitude. McHarg et al. (2007) find acceleration and deceleration values in the 10E5–10E10 m/s^2 range.[/quote]
[edited: fixed the exp-numbers]