3 ms·
Any of our resident scientists are welcome to correct me if I'm wrong, but I believe that most plasmas require much higher temperatures and pressures than a reg
by sq_ 7y ago
Any of our resident scientists are welcome to correct me if I'm wrong, but I believe that most plasmas require much higher temperatures and pressures than a regular fire like a candle can create.
The light we see from flames is mostly just photons emitting from the hot gases and other products of the combustion reaction, as far as I know.
- ncmncm 7y agoYes, light is 100% photons, or your money back. Considering that the overwhelming majority of the plasma in the universe is in interstellar space: no, extreme pressures and temperatures are not necessary. The absolute requirement is an ionization rate of more than 0.01%: more than one ion per 10000 neutral atoms. (Above that, regular gas dynamics don't work, and you need plasma dynamics.) This can be achieved by high-ish temperatures, or ionizing radiation, or various physical processes involving strong and varying electric and magnetic fields. Plasma dynamics are interesting because positive ions are at least 2K more massive than electrons. Any field that pushes the positive cores one way pushes the electrons 2k times faster in the other direction. Which, of couse generates other fields, and likely x-rays, too. Whenever you see some astronomy source claiming that x-rays imply a weirdly high temperature, you can be smug knowing that plasma is happy to emit x-rays at any temperature.
- sq_ 7y agoThanks for the rundown on plasmas there, that's super interesting. I always enjoy being taught new things, especially about physics!