Spark ionization

The formation of ions from a solid material by an intermittent electrical discharge.

This occurs when a solid material is vaporized and partially ionized by an intermittent electric discharge. Further ionization occurs in the discharge when gaseous atoms and small molecular moieties interact with energetic electrons in the intermittent discharge.

http://goldbook.iupac.org/S05780.html

Occurs when a solid sample is vaporized and partially ionized by an intermittent discharge. It is recommended that the word 'source' be dropped from this term.

Source:

PAC, 1991, 63, 1541 (Recommendations for nomenclature and symbolism for mass spectroscopy (including an appendix of terms used in vacuum technology). (Recommendations 1991)) on page 1548

Orange Book, p. 204