System and methods for plasma application

A plasma device configured to receive ionizable media, comprising:

• an outer electrode having a substantially cylindrical tubular shape;
• and
• an inner electrode coaxially disposed within the outer electrode, the inner electrode including an end distal portion extending distally past a distal end of the outer electrode and an insulative layer that extends up to the distal end of the outer electrode and covers the inner electrode at least up to the end distal portion of the inner electrode such that the end distal portion of the inner electrode is un-insulated,
• the insulative layer configured to limit plasma effluent to the end distal portion and to provide a source of secondarily-emitted electrons to form an electron sheath layer about the inner electrode end distal portion.

A plasma system, comprising:

• an outer electrode having a substantially cylindrical tubular shape;
• and
• an inner electrode coaxially disposed within the outer electrode, the inner electrode includes an end distal portion extending distally past a distal end of the outer electrode and an insulative layer that extends up to the distal end of the outer electrode and covers the inner electrode at least up to the end distal portion of the inner electrode such that the end distal portion of the inner electrode is un-insulated, the insulative layer configured to limit plasma effluent to the end distal portion and to provide a source of secondarily-emitted electrons;
• an ionizable media source coupled to the plasma device and configured to supply ionizable media thereto;
• and
• a power source coupled to the inner and outer electrodes and configured to ignite the ionizable media at the plasma device to form a plasma effluent having an electron sheath layer of a predetermined thickness formed from the secondarily-emitted electrons, the electron sheath layer being formed about the end distal portion of the inner electrode.