Plasma sheath

A plasma sheath is a boundary layer that forms around objects immersed in a plasma—a hot, ionized gas with free-moving charged particles. When the plasma comes into contact with a surface, electrons and ions interact differently, often causing a buildup of negative charge near the surface. This creates an electric field that repels some electrons and attracts positive ions, stabilizing the charge distribution. The sheath essentially acts as a protective barrier, influencing how particles transfer energy and momentum between the plasma and the object, which is important in fields like space physics, plasma technology, and spacecraft design.