Finite element analysis of an atmospheric pressure RF-excited plasma needle

Y. Sakiyama, D. B. Graves

Research output: Contribution to journalArticlepeer-review

85 Scopus citations


We report results from a two-dimensional, axisymmetric numerical simulation of the plasma needle, powered at 13.56 MHz. The atmospheric pressure discharge is simulated in helium with a small amount of nitrogen. The needle has a point-to-plane geometry with a radius of 30 νm at the tip and an inter-electrode gap of 1 mm. We employ the one-moment fluid model with local field approximation. The coupled continuity equations for electrons, ions and metastables are solved with Poisson's equation using the finite element method with an unstructured grid. The discharge voltage-power characteristic demonstrates a region in which multiple solutions exist for a given applied RF voltage. This mode transition in the plasma needle resembles an α-γ transition from a lower plasma density regime with a relatively thick sheath at the needle tip to a higher plasma density regime with a relatively thin sheath at the needle tip.

Original languageEnglish (US)
Article numberS01
Pages (from-to)3451-3456
Number of pages6
JournalJournal of Physics D: Applied Physics
Issue number16
StatePublished - Aug 21 2006
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Acoustics and Ultrasonics
  • Surfaces, Coatings and Films


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