Interaction of atmospheric pressure helium plasma jets with hollow dielectric targets: Shallow and deep grooves

The results of a computational study of helium plasma jet interaction with hollow dielectric grooves of various sizes are presented. It is shown that the character of interaction of ionization waves formed in plasma jets with treated objects depends substantially on the value of the dielectric permittivity of the groove material. For grooves with low permittivities, ionization waves penetrate inside and touch the bottom of the groove. For grooves with high permittivities, the reflected waves are formed after the contact of primary ionization wave with the groove edges, thus hindering penetration of plasma inside the groove interior.