Ecton (physics)

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Ectons are the smallest micro-explosions in the course of an arc evaporation . Each ecton releases a multitude of particles, electrons , ions , atoms and liquid clusters .

The Ecton model was introduced in 1990 by the Russian physicist Gennady Mesyats . The term "Ecton" is an artificially created word. The first two letters stand for the English e xplosive c enter and the ending -other is an indication of the particle nature of this phenomenon.

The model explains why the properties of the released ions depend little on the current density over a wide range of macroscopic current densities.

The concept of the "ecton" has received little attention.

Operations

The left picture shows the arc between the igniter and the cathode material, as well as the formation of an ecton. In the right picture, the resulting plasma torch with the emitted particles.

The evaporation of the cathode does not proceed continuously, but due to thermal instability in the form of a fractal hierarchy of ever smaller micro-explosions, the smallest units of which are the ectons. Ectones emanate from local peaks and leave funnel-shaped craters. The frequent repetition of this process creates a kind of crater landscape on the cathode surface.

An Ecton has a size of about one micrometer and a lifetime of about 10 ns with an emission of about 10 11 electrons (depending on the material). In this short time, the cathode material changes from the solid state of aggregation to a plasma , whereby a phase transition from liquid to gas does not occur due to the far supercritical pressure .

literature

  • André Anders: Cathodic Arcs - From Fractal Spots to Energetic Condensation . Springer, 2008, ISBN 978-0-387-79107-4 .
  • André Anders: The evolution of ion charge states in cathodic vacuum arc plasmas: A review. , Plasma Sources Sci. Technol. 21, 2012, doi : 10.1088 / 0963-0252 / 21/3/035014 , ( online ).
  • Ingmar Kleberg: The dynamics of cathodic focal points in an external magnetic field. Dissertation, 2001 ( Online ; PDF; 2.6 MB)
  • GA Mesyats: Properties of ectons in a vacuum discharge. Proc.XVIth ISDEIV, Moscow 1994, SPIE Vol. 2259.25

Individual evidence

  1. ↑ Different in 2012