> But plasma is not electromagnetic. It’s ionized gas.
Ions are electrically charged particles... https://en.wikipedia.org/wiki/Ion
... and plasma is an excellent conductor of electricity. https://en.wikipedia.org/wiki/Electrical_resistivity_and_conductivity#Plasma
“For many purposes, the conductivity of a plasma may be treated as infinite.”
Ions are electrically charged particles
I know what ions are. But they are not the carriers of electromagnetism: photons are (visible light, UV, gamma rays, infrared, photons). Cosmic rays and solar wind particles consists of ions, not photons.