Dusty Plasma
A complex plasma containing solid nanometer-to-micrometer scale dust grains that collect high negative charges from surrounding plasma electrons.
Governing formula
Q_dust ~ - 10³ e to - 10⁵ e (Charged Micron Dust Grains)
SI unit
μm (Dust Size) & Charged State
In depth
Because electrons have higher thermal velocities than ions, dust grains charge negatively until floating potential is reached (~10⁴ electrons per grain). Strongly coupled dust grains arrange into ordered 2D and 3D 'plasma crystals'.
Examples in the real world
Saturn's dusty rings, noctilucent clouds in Earth's upper mesosphere, and industrial semiconductor processing contamination.