From recent tests with an intermittent carbon arc I observed with a cheap software-based RF spectrum analyzer somewhat familiar spectra (30–1750 MHz):
The first especially reminded me of the one shown by Renzo Mondaini in his Mizuno-style plasma electrolysis setup as described in this other thread (0–2000 MHz):
Upon investigation it appears that similar plasma discharge systems show likewise a similar RF spectrum. For example, the one shown in this old paper by Iorio–Cirillo also looks familiar and more similar to the second I posted above (0–1000 MHz):
I'm not quite sure but I suspect that the above graphs show broadband RF noise with decay characteristics typical of high-frequency rate spark gaps/transmitters (as used in early radio). I couldn't find many examples but see for example the blue area in this graph from: https://www.nutsvolts.com/maga…ng_something_from_nothing
Then, the peaks and valleys observed in the actual experiments, as well as the noise floor, would mainly depend on the resonant characteristics of the antenna and receiver used. In the first two graphs I posted, the first was made with a ~60 cm long whip antenna, and the second with the same extended to 26 cm. It turns out (not unexpectedly, in retrospect) that difference in the location of the peaks is proportional to ratio of the antenna lengths. In other words the peaks are a function of antenna geometry rather than the actual reactions occurring in the spark gap/discharge, although this might not necessarily always be the case for all experiments.
Is there a specific name or concise mathematical relationship for the type of RF noise observed in these experiments or spark gaps in general? Are there other related examples from the LENR field?