Complex Plasmas and Dusty Plasma Phenomena

Complex plasmas—also referred to as dusty plasmas—consist of electrons, ions, neutral gas and micron-sized solid particles that become highly charged and interact via screened Coulomb forces. Under appropriate laboratory or microgravity conditions these systems exhibit strong coupling, leading to liquid- and solid-like states, wave propagation, phase transitions and self-organised structures such as plasma crystals and particle chains. The interplay between electrostatic forces, plasma flow and external fields gives rise to phenomena ranging from void formation and heartbeat instabilities in microgravity to thermophoretically driven particle motion and nonreciprocal interactions at ambient pressure. Studies span fundamental physics—exploring melting via Berezinskii–Kosterlitz–Thouless mechanisms, defect dynamics in two-dimensional lattices and transport in electrorheological plasmas—to practical applications in materials processing, fusion‐device wall conditioning and astrophysical ice formation. Advances in diagnostics, from high-resolution imaging to spectral analysis, continue to reveal the multi-scale character of complex plasma behaviour and its relevance to both industrial technology and cosmic environments.

Research from Nature Portfolio

Recent experimental work has elucidated the melting dynamics of quasi-two-dimensional dusty plasma crystals. By inducing controlled laser heating in an RF discharge, a two-stage transition from solid to hexatic and from hexatic to liquid phases was characterised through orientational and translational order parameters. Analysis of defect proliferation and dislocation core energies confirmed predictions of topological melting theory, establishing a quantitative link between particle-scale dynamics and continuum models. In complementary studies, the effective forces between microparticles suspended in an anisotropic plasma sheath were measured without external perturbations. A spectral-density approach, accounting for random and dissipative processes, directly revealed nonreciprocal interaction forces arising from asymmetrical charge fluctuations. This methodology offers a robust route to quantify action–reaction symmetry breaking in driven complex plasmas.

Complex Plasmas and Dusty Plasma Phenomena publication trend

The graph below shows the total number of articles in complex plasmas and dusty plasma phenomena across all publications each year (not limited to Nature Index journals).

Technical terms

Complex plasma: Ionised gas containing micron-sized particles that acquire large electric charges and interact via screened Coulomb forces.

Dusty plasma: Synonymous with complex plasma, emphasising the role of solid dust grains within the plasma medium.

Plasma sheath: Boundary layer adjacent to surfaces or electrodes characterised by a significant potential drop and reduced plasma density.

Coulomb crystal: Ordered lattice of charged microparticles formed under strong coupling in a complex plasma.

Hexatic phase: Intermediate state exhibiting short-range translational disorder but quasi-long-range orientational order, as described by Berezinskii–Kosterlitz–Thouless theory.

Nonreciprocal interaction: Effective force between particles that violates Newton’s action–reaction symmetry due to flows, wakes or charge asymmetries in the plasma.

References

1. Avoiding dust contamination by near-plasma chemical surface engineering. Materials Today Nano (2024).
2. Phase and Morphology of Water-ice Grains Formed in a Cryogenic Laboratory Plasma. The Astrophysical Journal (2024).
3. Laser-induced melting of two-dimensional dusty plasma system in RF discharge. Scientific Reports (2021).
4. Experimental study of the nonreciprocal effective interactions between microparticles in an anisotropic plasma. Scientific Reports (2020).