Faraday Dark Space and the Positive Column

The colors shown in Table 6.1 are only approximate. Sometimes mixtures of colors are seen as gas pressure or applied voltages change or if impurities are present. 

The positive column is a region in which atoms, electrons, and ions are all present together in similar numbers, and it is referred to as a plasma. Again, as with the corona discharge, in mass spectrometry, plasmas are usually operated in gases at or near atmospheric pressure. 

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