This question can be broken down to some more specific question

• What is a concise measure of stability of a welding arc? (its Power emission with time, lateral fluctuation of ionized gas column, fluctuation in electrical conductivity profile or temperature profile)?
• How some metal silicates, oxalates, oxides etc. stabilize arc? is the stabilization due to short-lived radicals (that do not follow usual valency rules, typical in upper atmosphere and planetary nebula) from dissociation of anions? On does it have something with do to cations?
• While plasma cations can be almost completely stripped out off its electrons (including inner ones), which properties of cation nucleus would be suitable for arc stabilization ?
• How thermal-electrical conductivities and emissivities of an welding arc vary with nuclear charge and size of cations as well as free radicals and anions generated from starting anions that were included in welding flux?