Toxic plasma

It's been some time since I have posted a plasma picture, so here are some hollow cathodes burning in hydrogen. Yes, it is true, I have finally graduated to toxic gases (at least in the context of safety, hydrogen is considered toxic because, well, boom.), meaning I get to fight with automatic safety systems and valves and detectors each time I want to do an experiment.

At least I can now say "Oh, I work with toxic plasma" when somebody asks me what I am working on.

Unfortunately, hydrogen plasma is very similar in colour to argon plasma. It is quite different in behavior of course (even in this photo you can see that it is much more contained than argon plasma. This is because of differences in the mean free path of electrons). I would love to do some oxygen at some point, because that would be blue, but it is even more of a pain in the ass to use oxygen right after you have used hydrogen ore vice versa. Because, well, double-boom.

Also I am a bit sick and tired of taking pictures of plasmas. It's fun, but I still have no idea what's really going on physically speaking. I want to start measuring, but what? I am afraid the first thing will be optical spectroscopy again - a real pain in the ass. Well, at least I know more about it now...