Excitation of a plasma:
- By heating of a gas to extreme temperatures. This type of plasma excitation is present only in nature (stars)
- By ionising radiation: This type of plasma excitation is likewise only present in nature (absorption of high-level solar radiation in the ionosphere
- by strong electrical fields). This type of excitation generates lightning, corona and gas discharge in atmospheric plasma.
- By high-frequency electrical fields (HF excitation). This method is used to excite the low-pressure plasma. angeregt.
- In excited atoms, valence electrons are excited to higher energy levels. These excited atoms are highly reactive because the excited valence electrons are very easily released to binding partners.
Atoms are not always ionized in plasma. Often electrons are not completely removed, but only excited to higher energy levels.
Excited valence electrons easily fall back to their basic state under energy radiation. This radiation is responsible for the characteristic colour of the process gases.