Apparatus for atmospheric pressure pin-to-hole spark discharge and uses thereof

A method of treating a skin ulcer using non-thermal plasma, comprising:

• flowing a gas through a conduit capable of fluidically communicating gas, plasma, or both gas and plasma, therethrough, a first portion of the conduit capable of being connected to a gas supply, and a second portion of the conduit capable of emitting a plasma, the conduit comprising therewithin:
• a positive electrode comprising a sharp tip, the positive electrode capable of receiving a high voltage from a positive terminal of a high voltage power supply;
• a ground plate electrode comprising an opening passing through the plate, the opening characterized as having a dimension, d, the ground plate electrode capable of being in electrical communication with ground and a negative electrode of said high voltage power supply, the sharp tip of the positive electrode being axially displaced from the opening of the ground plate electrode by distance h, the distance h defining a spark zone between the sharp tip of the positive electrode and the opening of the ground plate electrode;
• wherein the sharp tip of the positive electrode, the opening of the ground plate electrode and the spark zone are located within the second portion of the conduit capable of emitting a plasma;
• and
• repeatedly charging and discharging a capacitative circuit electrically coupled to a high voltage power supply to provide a voltage of at least 500 V across the positive and ground negative to give rise to a pulsed spark discharge at a rate of at least 1 Hz in the spark zone;
• flowing the gas through the spark zone simultaneously with the creation of the pulsed spark discharge to give rise to a non-thermal plasma emitted from the second portion of the conduit, the non-thermal plasma comprising a predetermined concentration of nitric oxide (NO);
• and
• contacting a skin ulcer with said non-thermal plasma for sufficient time and intensity to give rise to healing of the skin ulcer,
• wherein the cold spark discharge voltage is in the range of from about 500 V to about 5 kV,
• wherein the diameter of the non-thermal plasma is in the range of from about 3 mm to about 5 mm,
• wherein the pulsed spark discharge is pulsed at a frequency in the range of from about 1 Hz to about 30 Hz, and
• wherein the duration of the pulsed spark discharge is in the range of from about 5 microseconds to about 50 microseconds.