Plasmapuolella

Plasmapuolella is a Finnish-language term used in plasma physics to describe the plasma-facing side of a boundary. It designates the region of the plasma immediately adjacent to a surface, such as a solid wall, a reactor boundary, or another interface, as distinct from the material side of the boundary.

In this region, the plasma properties are governed by a sheath—the quasi-neutral plasma gives way to a non-neutral layer that sustains a potential drop. This sheath directs a flux of ions to the surface and controls energy deposition, sputtering, and surface modification. The characteristic length scale is the Debye length, and the Bohm criterion sets conditions for boundary entry of ions.

Plasmapuolella is a key concept in both fusion research and industrial plasma processing. In fusion devices, it accompanies studies of plasma-facing components and heat loads. In processing reactors, it relates to etching and coating processes where plasma-surface interactions determine yields and surface integrity.

Research methods used to study plasmapuolella include Langmuir probes and emissive probes to measure plasma parameters near walls, optical emission spectroscopy to monitor species and energies, and computational models that couple plasma physics with material response, such as sputtering and deposition models within plasma-material interaction frameworks.