Ion orbits in a cylindrical Langmuir probe
- Dipartimento di Chimica dell'Universita degli Studi di Bari and IMIP-CNR, sect. Bari, via Orabona 4, 70126 Bari (Italy)
It has been suggested that in weakly collisional sheaths, potential wells and barriers could appear due to ion-neutral momentum and charge transfer collisions. These can cause the presence of repulsed and trapped ions in the region surrounding a negatively biased Langmuir probe, invalidating the commonly used orbital-motion-limited theory of ion current. This is still an open question concerning also the charging and shielding of dust grains, and at present, no fully self-consistent treatment exists. For this reason, a particle-in-cell/test-particle Monte Carlo simulation of the dynamics of an argon plasma in the region surrounding an attracting cylindrical probe at medium gas pressure has been developed. The results of the present simulation for different probe potentials and discharge pressures demonstrate the complex structure of electric potential around the probe and the failure of collisionless theories.
- OSTI ID:
- 20782762
- Journal Information:
- Physics of Plasmas, Vol. 13, Issue 4; Other Information: DOI: 10.1063/1.2181971; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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