1. Waves and solitons in complex plasma and the MPE - UoL team D. Samsonov The University of Liverpool, Liverpool, UK

2. Complex plasmas in basics science - linear and nonlinear waves - solitons - Mach cones (wakes) - shock waves - phase transitions - transport properties - nonlinear phenomena - model systems

3. Main features of complex plasmas low oscillation frequency (1 - 100Hz) due to high mass low damping rate (~1 - 100s -1 ) compared to colloids can be in gaseous, liquid or crystalline states dynamics can be studied at the kinetic level with a video camera (or observed by the naked eye) can be used as a macroscopic model system for studying waves, shocks, solitons, etc. large interparticle spacing (30µm - 1mm)

4. Laboratory experiments (2D) argon, 1-2 Pa, 1.5-2 sccm 2-100 W ccrf-discharge 8.9  m plastic microspheres monolayer hexagonal lattice 0.2-1mm grain separation green laser illumination top view video camera

5. Data analysis particle identification particle tracking - yields velocity Voronoi analysis - number density averaging in bins - kinetic temperature

6. 3D molecular dynamics simulation Particles interact via Yukawa potential Particles are strongly confined vertically Particles are weakly confined horizontally No plasma, damping due to neutral friction Equations of motion are solved Particles are seeded randomly Code is run to equilibrate the resulting monolayer Excitation is applied

7. Phase states solid: hexagonal crystal lattice long range correlation liquid: some order short range correlation gas: grains move fast grain position are uncorrelated

8. Linear waves Wave modes in a monolayer lattice: Compressional (longitudinal) - acoustic Shear (transverse) - acoustic Vertical (transverse) - optical

9. Lattice waves phonon spectra short wavelength - anisitropic long wavelength - isotropic compressional mode shear mode wave polarization longitudinal transverse mixed PRE 68, 035401, (2003)

10. Dust-thermal waves PRL 94, 045001, (2005) analogous to sound waves in gases due to pressure term dominates at high temperature v DT =(  k B T/m d ) 1/2  =2 in 2D case  =5/3 in 3D case

11. Vertical wave packets

12. top view stripes move left packet moves right inverse optical dispersion V gr = 4 mm/s V ph = -290 mm/s C DL = 35 mm/s PRE 71, 026410, (2005)

13. Solitons

14. localized (solitary) wave soliton parameter: AL 2 = const damping due to friction dissipative solitons described by the KdV equation weak nonlinearity weak dispersion multiple solitons are possible PRL 88, 095004, (2002)

15. Shock waves

16. Number densityKinetic temperature Flow velocityDefect density

17. Experiment Molecular dynamics simulation Shock (velocity vector map)

18. Space experiments PKE-Nefedov PKE-3 PKE-3+ PKE-4 PKE-….

19. Role of Gravity Observation on Earth Observation under µg Side view of a complex plasma

20. Waves in a 3D complex plasma Electrode voltage modulation excites waves frequency is varied dispersion is measured fit with DAW and DLW theory grain charge is determined Q=1600-2200e Phys. Plasmas 10, 1, (2003)

21. PK4 experiment

22. Plans for future experiments obtain large monolayer crystals reduce damping rate linear waves in binary mixtures vertical waves solitons and their interaction shocks and their interaction

23. Summary complex plasmas model real systems at the kinetic level (basic physics) dynamics can be studied linear waves solitons shocks other dynamic phenomena