Plasma-wall interactions in DC discharges and sheath of Langmuir probes

• Published in: The European physical journal. ST, Special topics Special topics, 2013-10, Vol.222 (9), p.2143-2156
• Main Authors: Cenian, A., Rachubinski, H., Chernukho, A., Dudeck, M.
• Format: Article
• Language: English
• Subjects: Atomic; Classical and Continuum Physics; Condensed Matter Physics; Exact sciences and technology; Materials Science; Measurement Science and Instrumentation; Molecular; Optical and Plasma Physics; Physics; Physics and Astronomy; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges; Plasma interactions (nonlaser); Plasma-wall interactions; boundary layer effects; Review
• ISSN: 1951-6355; 1951-6401
• DOI: 10.1140/epjst/e2013-01991-y

The plasma-wall interactions in various DC discharges and sheath of Langmuir probe are analyzed and discussed. The methods of their investigations are discussed including fluid and PIC MC. Various assumptions used in fluid models e.g. plasma neutrality, Bohm criterion, Boltzmann electrons approximation, etc. are analyzed. Ion heating and electron cooling effect at the DC plasma wall is discussed and explained. Langmuir probes measurements in high-temperature and ion thruster plasma are analyzed. The secondary electron emission influences the IV characteristic of Langmuir probe especially at positive voltages. However, only elastic reflection processes really contribute significantly to the probe current. The elastic SEE processes reflect electrons from probe with the same relatively high speed. It was observed that the axial magnetic field influences probe characteristics and floating potential more significantly than radial field. The axial field deflects all electrons approaching probe.