JMC Posted August 5, 2020 Share Posted August 5, 2020 Browsing ebay the other day I came across something called an Arc lighter. This generates an air plasma between its electrodes as an alternative to a traditional fluid based lighter. As it didn't cost much I thought I'd get one and see what the emission spectra was like. Here's the lighter, without and with being lit. When I put my cosine correcter terminated optical fiber close to it (very close, about 5mm) I just about managed to get the irradiance spectra; Very similar to what I'd expect for an air plasma which was good to see, but really not very bright. Also took some pictures of it in UV, using the ACS converted Nikon d810 (similar response to Baader U), and Rayfact 105mm UV lens. Whitebalanced in Darktable, and cropped from originals. Couple of different exposures. Longer exposure (ISO1000, 6s, f16). Short exposure (ISO1000, 1/2s f16) Obviously with the longer exposure the emission over saturates and goes white, but you can see it illuminating the lighter a bit. At the shorter exposure, the 2 back electrodes are behaving differently to the other 2. I can just about see a hint of yellow in the bulk of the plasma, which make sense given the large emission peak in the 340nm region. Overall not the brightest little UV source (I wont be replacing my Xenon flashes any time soon), but an interesting little device. Part of me wonders whether it shocks like a taser, but I currently have no plans for putting my fingers on the electrodes to try it..... Link to comment
Cadmium Posted August 5, 2020 Share Posted August 5, 2020 Jonathan, Very interesting! Thanks. Link to comment
ulf Posted August 5, 2020 Share Posted August 5, 2020 I wonder how much EMC-noise emission it have. Link to comment
Stefano Posted August 5, 2020 Share Posted August 5, 2020 That's an interesting spectrum. A peak every 20 nm. Link to comment
colinbm Posted August 5, 2020 Share Posted August 5, 2020 I wonder what volts & amps are involved here ? Link to comment
Stefano Posted August 5, 2020 Share Posted August 5, 2020 I wonder what volts & amps are involved here ?Maybe 20-30 kV (assuming a 1 cm gap) and probably a lot of current for a short period of time. The average current is probably very low. Link to comment
JMC Posted August 5, 2020 Author Share Posted August 5, 2020 A quick search led me to this spectra; From here - https://www.researchgate.net/publication/255909017_Characterization_of_a_Novel_Atmospheric_Air_Cold_Plasma_System_for_Treatment_of_Biomaterials Peaks look to be a pretty good match. Link to comment
Stefano Posted August 5, 2020 Share Posted August 5, 2020 Yes, it looks pretty similar. Link to comment
OlDoinyo Posted August 5, 2020 Share Posted August 5, 2020 I have long wanted to try lightning photography at night in UV. This could at least be considered a proof of concept--there would indeed be UV to record. Link to comment
Andy Perrin Posted August 5, 2020 Share Posted August 5, 2020 Well that is very cool, both as a device concept and the measured spectrum you made. Link to comment
dabateman Posted August 5, 2020 Share Posted August 5, 2020 I have long wanted to try lightning photography at night in UV. This could at least be considered a proof of concept--there would indeed be UV to record. I think a 365nm led flashlight would be much brighter, safer and more ideal than a literal torch for lighting. Jonathan,Very cool. This could help in building a vaporized iodine lamp that I have always wanted. That way I can get a 207nm line.I might consider something like this. Link to comment
colinbm Posted August 5, 2020 Share Posted August 5, 2020 I wonder if a Plasma Cutting Torch has the same spectrum ? Link to comment
colinbm Posted August 6, 2020 Share Posted August 6, 2020 Using your microwave oven to make blue violet plasma....Don't tell Mum Link to comment
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