Electrodeless Double-Headed Streamer Discharges from an Isolated Ionization Column in Atmospheric Conditions
Résumé
This poster presents a groundbreaking experimental model that successfully reproduces the natural atmospheric phenomenon of double-headed streamers (DHS) in a laboratory setting at ground pressure. This is the first of its kind to replicate the inception of an electrodeless DHS, mirroring various observations made by the atmospheric electricity community [1]. By utilizing guided ionization waves from an Atmospheric Pressure Plasma Jet (APPJ) device, the experiment achieved excellent reproducibility and predictability in triggering DHS formation. The experimental approach effectively created conditions that align with several assumptions, such as maintaining an initial preionized column of free charges before breakdown [2]. This model closely matches numerous simulation results found in modeling literature [2, 3]. The positive and negative streamers were distinctly identified, showing simultaneous counter-propagation from the breakdown location. The high stability of the discharge allowed for advanced diagnostics, including time- and space-resolved optical emission spectroscopy. This enabled the first measurements of velocity growth, gas temperature, and electric field of a DHS. The electric field values confirmed the identification of positive and negative streamers. Notably, the electric field diagnostics revealed that a DHS can ignite under sub-breakdown conditions, highlighting the essential role of preionization in DHS formation. These findings support the theory proposed in [2]. While further research is needed to fully understand the underlying mechanisms, these results pave the way for deeper investigations into the early stages of sprite discharges and other poorly understood phenomena in atmospheric electricity using affordable laboratory-scale experiments. [1] Pasko VP, Inan US, Bell TF. Geophys Res Lett. 1998;25(12):2123–6. [2] Liu N, Kosar B, Sadighi S, Dwyer JR, Rassoul HK. Phys Rev Lett. 2012 Jul 10;109(2):025002. [3] Luque A, Ratushnaya V, Ebert U. J Phys D: Appl Phys. 2008 Nov 20;41(23):234005.