Nowadays designation for all strong current discharges at medium and high pressure that involve a hot cathode . Anode Positive elektrode of an electric discharge. All matter is built from smallest units, the atoms, which give the substance its chemical and physical properties.
Atoms consist of a positively charged atomic nucleus and a surrounding cloud of electrons .
The electric charge of the nucleus and of the electrons is opposite so that the net charge of the atom is zero. The diameter of the atomic nucleus is only 10 -14 m, which is 10,000 times smaller than the electron shell. The nucleus contains protons and neutrons . For stability reasons, heavy elements have more neutrons than protons. The phenomenon is called Aurora australis on the southern hemisphere.