Answers are grounded in this paper and cite their sources.
A macroscopic Coulomb crystal of solid particles in a plasma has been observed. Images of a cloud of 7-μm "dust" particles, which are charged and levitated in a weakly ionized argon plasma, reveal a hexagonal crystal structure. The crystal is visible to the unaided eye. The particles are cooled by neutral gas to 310 K, and their charge is $>9800e$, corresponding to a Coulomb coupling parameter Γ>20 700. For such a large Γ value, strongly coupled plasma theory predicts that the particles should organize in a Coulomb solid, in agreement with our observations.
No takes yet. Share an insight, caveat, or question.
Thomas et al. (1994) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: