Holger Kersten. Complex Plasmas

Transcription

1 Institut für Experimentelle und Angewandte Physik Institute for Experimental and Applied Physics Progress in Complex Plasma Research Holger Kersten IEAP, University of Kiel Graduate Summer Institute Complex Plasmas University of Greifswald August 05, 2010 Name des Vortragenden Group Plasma Vortragstitel Technology Datum

2 outline complex plasmas publications on complex plasmas transregional collaborative research centre TR24 research activities summary interaction (charging, g forces, structures, waves) modeling, simulation diagnostics of complex (dusty) plasmas particles as plasma probes application of complex plasmas (technology, fusion) reactive plasmas microplasmas

3 complex plasmas

4 complex plasmas NRC report (1) Explosive instability in plasmas (2) Multiphase plasma dynamics (3) Particle accelerations and energetic particles in plasmas (4) Turbulence and transport in plasmas (5) Magnetic self-organisation in plasmas Complex Plasma (6) Correlations in plasmas

5 complex plasmas Complex plasmas are distinct from conventional plasmas by the presence of additional plasma constituents, by particle correlations, by interactions with solid surfaces, which decisively influence the behavior of the plasma and provide important and novel properties. Recent developments demand a redefinition and thematic extension of the classical plasma concept. Complex plasma systems which contain, for example, colloidal nano/microscopic particles (dust) have recently been widely discussed in the physics and chemistry of plasmas, ionized gases, space physics and astrophysics, plasma diagnostics, aswellasinmaterials research and engineering.

6 complex plasmas e negative ions + DUST - R PLASMA m metastables reactive species, molecules particle plasma sheath surface, deposited thin films + SOLID F.X. Bronold (Wed) P. Ludwig g( (Wed) N. Horing (Wed) H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum

7 complex plasmas a prominent feature of complex plasmas is the existence of many different length and time scales for example, elementary reactions and negative ions affect the macrostructure and stability of discharges boundary layers are determined by the neutral and charged particle fluxes to the surface and the reactions and reflux of neutrals from the surface as well as secondary particle emission (electrons, negative ions) microscopic charging processes in dusty plasmas affect the global charge balance of the discharge

8 M. Bonitz (today) D. Gericke (today) complex plasmas

9 astrophysics (formation of stars, comets, planetary rings) Goertz, Mendis, Sedlmayer, Morfill complex plasmas basic research : plasma crystals Piel, Morfill, Goree, Fortov, Melzer, Lampe dust as fault in semiconductor processing Selwyn, Bouchoule, Kroesen, Stoffels, Hollenstein 1 m generation and modification of powders (technological application) micro-probes for diagnostics H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum

10 complex plasmas Particle-containing plasmas, dynamics and order phenomena Stellar astrophysics Solar physics Aurora Plasma crystals Plasma science is a key field of basic and applied research with proven impact on society and economy Diamond synthesis Surface modificationsilicon etching Film deposition Light sources Reactivity and surface processes

11 complex plasma Complex plasma Basic Plasma Physics Astrophysics Applications particle charging, interstellar clouds, powder synthesis strongly coupled plasma waves polarization origin of powder and modification, plasma processing

12 complex plasmas publications on complex plasmas

13 literature on physics of complex plasmas S.V. Vladimirov, K. Ostrikov, A.A. Samarian, Physics and Applications of Complex Plasmas, Imperial College Press London, P.K. Shukla, A.A. Mamun, Introduction to Dusty Plasma Physics, IOP Publishing London, A. Bouchoule, Dusty Plasmas Wiley, VF V. Fortov, I. Ik Iakubov, A. Khrapak, Physics of Strongly Coupled Plasmas, Oxford University Press, V. Fortov, G.E. Morfill, Complex and Dusty Plasmas: From Laboratory to Space, CRC Press Taylor & Francis, 2009

14 literature on physics of complex plasmas A. Melzer, J. Goree, Fundamentals of Dusty Plasmas, Wiley, 2008, 129. R. Hippler, H. Kersten, Applications of Dusty Plasmas, Wiley, 2008, 787.

15 literature on physics of complex plasmas M. Bonitz, N. Horing, P. Ludwig, Springer, Complex plasmas differ from traditional plasmas in many ways: these are low- temperature high pressure systems containing nanometer to micrometer size particles which may be highly charged and strongly interacting. The particles may be chemically reacting or be in contact with solid surfaces, and the electrons may show quantum bh behaviour. These interestingi properties have ld led to many applications of complex plasmas in technology, medicine and science. Yet complex plasmas are extremely complicated, both experimentally and theoretically, and require a variety of new approaches which go beyond standard plasma physics courses. This book fills this gap presenting an introduction to theory, experiment and computer simulation in this field. Based on tutorial lectures at a very successful recent Summer Institute, the presentation is ideally suited for graduate students, plasma physicists i and experienced undergraduates.

16 publications on physics of complex plasmas? Plasma crystals Plasma processing

17 Institut für Experimentelle und Angewandte Physik New J. Phys. 5 (March 2003) EDITORIAL Focus on Complex (Dusty) Plasmas The research field of complex (dusty) plasmas has seen a sustained rapid growth in recent years. This can be attributed to the remarkable discovery of new states of (soft) matter - the liquid and crystalline plasmas - in Following this discovery, many researchers throughout the world decided to explore and investigate the new physics that was beckoning. Now the field produces about one scientific publication per day, many links to other disciplines are being forged (e.g. colloid physics, solid state, granular media, environmental research, etc) and application potentials are under investigation, too (e.g. nanostructured materials, plasma cleaning devices, adaptive electrodes, particle manipulation and modification, etc). The young field of complex (dusty) plasmas is beginning to come of age. This seemed like an excellent time to produce a Focus Issue on the topic. Through the diversity of the contributions the reader is able to get a synoptic view of the field which, of course, a review article cannot provide. The papers cover basic aspects of dust-plasma interactions in the laboratory, under microgravity conditions and in space, as well as the application of plasma-processed micro-particles. The contributions tib ti focus on the lt latestt scientific advances in complex plasmas. Judging from the huge response to the announcement of the Focus Issue in New Journal of Physics, we, the editors, conclude that the field is still growing and that the timing for the Focus Issue is just right! We would like to express our appreciation to Alexander Bradshaw who initiated this Focus Issue. Finally, we wish to thank the editorial team, especially Tim Smith, the many referees and the contributors for their excellent work. Greg Morfill, Max-Planck-Institut für Extraterrestrische Physik, Garching, Germany Holger Kersten, Institut für Niedertemperatur-Plasmaphysik e.v. Greifswald, Germany /2003 H.K., PL LASMA 2003, Warsaw, 11/09/ WWW: DOI: / /5/1/001 H. Kersten Overview on Complex Plasmas 07/30/2008 Name des Vortragenden Vortragstitel Datum

18 publications on physics of complex plasmas

19 International Conference on Physics of Dusty Plasmas Hakone, 1999 Durban, 2002 Orleans, 2005 Azores, 2008

20 Research Center on Physics of Complex Plasmas Collaborative Research Center Transregio 24 "Fundamentals of Complex Plasmas" Greifswald - Kiel

21 complex plasmas transregional collaborative research centre TR24

22 complex plasma studies in TR 24 Plasma size From large and stable plasmas to microplasmas. Plasma pressure From low pressure to atmospheric pressure. Plasma chemistry Time scales Correlations Quantum effects From simple gases to complex and reactive molecular plasmas and their interaction with condensed matter. From electron and ion dynamics to chemical reactions and collective behaviour of massive dust particles. Dynamics and thermodynamics of strongly correlated plasmas and particle clouds. Plasma boundary, plasma physics meets solid state physics.

23 complex plasma studies in TR 24 aim : comprehensive study of plasmas that contain nanometer or micrometer- sized particles, reactive molecules or radicals, or that are influenced by physical and chemical reactions at surfaces two interrelated research areas : # stability, wave propagation, order phenomena, correlation effects and phase transitions in negative ion or particle containing plasmas # spatio-temporal behavior and local plasma-chemical parameters of non-stationary molecular plasmas, as well as the particle synthesis in reactive plasmas and chemical processes at particle or solid surfaces are studied close network of experimental investigations, analytical theory, computer simulations and advanced d data analysis methods H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum

24 complex plasma studies in TR 24 the investigations in the network range from reactive and multi-component plasmas, dusty plasmas, plasmas containing nano-particles and plasmas interacting with solid surfaces the complexity of the investigated systems has many roots, among them the large number of involved species, the complicated atomic processes in the volume and at surfaces strong correlation effects lead to static and dynamic plasma properties which are otherwise found in liquids and solids only of great importance here is the determination of underlying general characteristics, which may have the form of scaling laws or comprehensive model equations

25 complex plasma studies in TR 24 (1) Application of innovative experimental techniques to study dynamical processes in dusty and reactive plasmas on different spatial and temporal scales. (2) Qualitatively novel insights in reactive and dusty plasmas by combining theory, simulation and experiment. (3) Theoretical understanding of coupling effects in 3D Yukawa balls, and microscopic c approach of particle charging g in plasmas. (4) Improved knowledge about plasma chemical processes in plasma bulk and on surfaces from transient species kinetics.

26 complex plasma studies in TR 24 GREIFSWALD KIEL Non-linear dynamics in plasmas Electron kinetics Plasma chemistry Waves, instabilities, turbulence Plasma-surface interaction, plasma boundary and materials science Strongly correlated plasmas and dusty plasmas

27 complex plasma studies in TR 24 systematic investigations of the following fundamental aspects: # Forces, confinement, order phenomena and collective processes in dusty plasmas # Chemical and physical processes of ions, atoms and molecules in the plasma and the interaction of the plasma with particles and solid surfaces # Formation and properties of nano-particles in plasmas and deposition on surfaces # Waves, self-organization and plasma stability in multi-species plasmas # Correlations and collective effects in many-particle systems

28 complex plasma studies in TR 24 Fundamental processes in multi-species plasmas and interaction with boundaries Combining plasma and materials science for novel composite films Role of magnetic fields on plasma processes with particles Role of boundaries in reactive and dusty plasma systems Synthesis of new functional materials Fundamental mechanisms in strongly coupled Coulomb systems Simulations of multi-scale and correlation problems Progress in plasma catalysis Self-consistent modelling/simulation of reactive and dusty plasma systems Inclusion of quantum effects

29 research activities interaction (charging, forces, structures, waves)

30 interaction plasma - particles dust cloud F g ~ r s 3 F el ~ r s E F n ~ r s3 (v s -v n ) F el,2 F ion ~ r s2 v i 2 F th ~ r s 2 T force (N N) F el,1 F ion F th electrode wall (1) : E = 100V/m sheath (2) : E = 10 4 V/m 1. gravitation 2. neutral drag force (viscosity) particle radius(µm) 3. ion drag force 4. electrostatic force (E-field) 5. thermophoresis (temperature gradient) 6. photophoresis (radiation) 7. inter grain force (Coulomb) A. Melzer (Mon) F g H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum

31 interaction plasma - particles PULVA-INP

32 plasma crystal Coulomb coupling parameter: C 170 lattice parameter ~ ( D /d) < 1 interaction plasma - particles plasma crystal with interesting properties global neutrality fast response to changes of surrounding plasma small damping simple experimental control and diagnostics Coulomb interaction strong coupling complex plasma plasma crystal provides possibilities model system for phase transitions, lattices, defects,... study of non-linear effects in micro crystals plasma diagnostics, transport processes... G.E.Morfill, H.Thomas, J.Vac.Sci.Technol. A14/2(1996), 490. H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum

33 interaction plasma - particles A. Melzer (Mon) P. Hartmann (Tue) H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum

34 interaction plasma - particles Structure, confinement, metastable states, and dynamics of Yukawa balls in experiment, simulations and theory A. Melzer (Mon) D. Block (Mon) Phys. Rev. Letters 101(2008), (2006), Phys. Plasmas 15(2008), December 2, 2005 "The Hole Crystal" Particle dynamics, wave modes, dust-wave coupling of magnetized dusty yplasmas. Phys. Plasmas 14(2007) (2006) Coulomb crystal in two-component plasma. Impact on astrophysics, semiconductor physics. Phys. Rev. Letters 95 (2005),

35 interaction plasma - particles synthesized small particles (~100nm) show vortices and voids due to the ion drag M42 structures, similar to Orion nebula, but at different scales

36 interaction plasma - particles dust in magnetized plasma drift waves DUSTWHEEL (A. Piel, F. Greiner et.al.)

37 research activities modeling, simulation

38 modelling, simulation Q 4 10 Q r kt D. Gericke (today) V. Land (Mon) Colloidal suspension r m T mk Plasma crystal: Chu & I, PRL (1994); Thomas et al, PRL (1994); Hayashi & Tachibana, Jap. J. Appl. Phys (1994) Jupiter Itano et al, Science (1998) H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum

39 modelling, simulation T. Miksch (Mon) H. Kählert (Mon) T. Ott (Tue) Yukawa systems H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum

40 modelling, simulation 3D Coulomb Clusters (M. Bonitz, A. Melzer, D. Block et.al.)

41 modelling, simulation plasma boundary, particle charging (F.X. Bronold, H. Fehske et.al.)

42 research activities diagnostics of complex (dusty) plasmas

43 diagnostics of complex plasmas Basics Shielding Charging Forces on particles Waves in dusty plasmas plasma crystal powder in reactive plasmas dust in the universe Diagnostics I. Korolov (Wed) H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum

44 diagnostics of complex plasmas Diagnostic Techniques A. Melzer (Mon) Particle Dynamic Structure Single Static Particle Waves Transient Crystal Structure Particle t Motion Instabilities Equilibrium Position Transient Crystal Structure Particle Motion

45 vertical oscillations of dust particles, excited by applying a sinusoidal voltage to the segments below them determination of the particle charge diagnostics of complex plasmas 10Hz 12Hz 14Hz 16Hz 18Hz A. Melzer (Mon) H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum

46 diagnostics of complex plasmas methods for the determination of the particle charge driven particle oscillation about equilibrium by superposition of an external low-frequency voltage, laser-induced photodetachment of charge and subsequent detection by microwave interference methods or probes, formation of Mach cones by moving dust particles, measurement of electron density drop of the surrounding plasma by particle injection, estimations by model assumptions based on the particles spherical capacity or on the currents of charge carriers towards the dust grains, respectively..

47 diagnostics of complex plasmas observation of plasma crystals HeNe- Laser Dust particle CCD-Camera Grid electrode sheath edge v v (x) I particle plasma electrode E 0 E E (z) z 0 z powered electrode Laser diode ~ molch box filter _ RF voltage LF voltage generator generator D. Block (Mon) B. Buttenschön (Mon) H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum

48 diagnostics of complex plasmas D. Block, A. Melzer et.al. observation of 3D Yukawa balls by stereo imaging g or holograms

49 diagnostics of complex plasmas metastable diagnostics R. Hippler et.al.

50 research activities particles as plasma probes

51 particles as plasma probes method : experimental investigation of interaction between plasma parameters and the behaviour (r, t) of dust particles in the plasma for using in diagnostics aims : particles in plasma as electrostatic probes determination of local electric fields, especially in plasma sheath thermal probes fluorescent particles for the measurement of the energy fluxes micro-substrates investigatio of reactive processes on microscopic surfaces, diagnostics of radicals in plasma force probes determination ti of momentum transfer / forces modelling of particle charging H. Kersten (Wed) effect of additional plasma sources on the behaviour of micro-particles p (ion beam source, dc-magnetron, AE, ) H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum

52 particles as plasma probes V pl, n n, n e, n i, kt n, kt e, kt i ions v i sheath boundary E F E, F th F g, F i z 0 radius = R d charge = Z d e 0 z dsh T el rf powered electrode

53 particles as plasma probes ition [mm] trapping posi 7,4 7,3 7,2 7,1 7,0 6,9 6,8 6,7 6,6 6,5 6,4 6,3 6,2 6,1 6,0 5,9 5,8 5,7 5,6 p = 8 Pa, V bias = V 9.55 µm µm µm bias voltage [V] p = 8 Pa, V bias = V a = µm particle (r=4.775 µm) trapping in PerPlEx at 8 Pa Argon.

54 particles as plasma probes H. Kersten (Wed)

55 research activities application of complex plasmas (technology, fusion)

56 applications of complex plasmas The increased knowledge and ability to control particles in a plasma environment has recently led to new lines of technological research, namely the tailoring of particles with desired surface properties. Kersten,H., Deutsch,H., Stoffels,E., Stoffels,W.W.,, Kroesen,G.M.W.,, Hippler,R. Contrib.Plasma Phys. 41(2001), 598. particle synthesis and treatment A. Bouchoule et.al. G. Kroesen et.al. G. Selwyn et.al. J. Winter et.al. P. Roca i Cabarocas et.al. N. Sato et.al. C. Hollenstein et.al. S. Girshick et.al. etc.

57 applications of complex plasmas Nanoparticles as a critical step Formation of primary clusters e Particle growth Nucleation and cluster growth e, i Coagulation Typical evolution the coagulation step - requires a high density of nm size precursors - leads in irreversible way to macroscopic particles typical densities required in the range of cm -3 end : a dusty-dense plasma H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum

58 applications of complex plasmas Challenge: Syntheses of new functional materials Preparation of metal-polymer composites Plasma processes and energetic ions for material modification Nanostructuring of surfaces V. Zaporojtchenko (Thu) S. Bornholdt (Thu) L. Rosenthal (Thu)

59 applications of complex plasmas Industrial / technological interest : Dust particle contamination control of the industrial reactors; Particle synthesis (ex. SiC, SiN, CN, SiO x.); Particle treatment : Coating, functionalization,. Incorporation of nanoparticles in thin layers in order to improve their mechanical, optoelectronic properties;

60 applications of complex plasmas,,... dust ist one of the main problems for the semiconductor industry. Size of killer particles is rapidly shrinking into the nano-regime G.S. Selwyn et.al. YEAR Memory 1G 4G 16G 64G 256G Feature size, nm D killer particle, nm Source: National Technology Roadmap for Semiconductors Workshop, 1999 LB L. Boufendi et.al.

61 dust formation in fusion devices T. Klinger (Fri) M. Endler (Fri) Fusion on earth suffers from plasma-surface-interactions (PSI). PSI leads to material erosion and to dust formation. H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum

62 dust formation in fusion devices The presence of dust in fusion devices has important t consequences. Safety liberation of radioactivity violent chemical reactions T - inventory Plasma-dust-interaction impurities transport in the plasma edge performance of the core plasma Engineering closure of gaps heat transfer H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum

63 dust formation in fusion devices The controlled growth of small particles definitively happens in tokamaks. accretion from neutral C: hydrogen poor growth from hydrocarbons: hydrogen rich TEXTOR CH 4 and C 2 H 2 process plasma Tore Supra 100 nm EPII, Ruhr-Universität J. Winter, Plasma Phys. Contr. Fusion 40(1998)1201 E. Kovacevic et al. J. Appl. Phys. 93(2003)2924 P.Chappuis et al., J. Nucl. Mater (2001) 245 H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum

64 applications of complex plasmas external dc-magnetron and particles in plasma changes of the plasma sheath and the field (plasma density in trappping region) charge of the powder particles (additional electron flux) deposition of films onto particles (and heating) V. Stranak (Tue) dust particles as micro probes Ar (5 P) Pa), rf-plasma (5W) W), SiO 2 (15µm) magnetron on / off (50 W) Matyash,K.,Fröhlich,M., et.al.,, J.Phys.D: Appl.Phys. 37(2004), H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum

65 applications of complex plasmas Kersten,H, Thieme,G., et.al. Pure Appl. Chem. 77(2005)2, 415. H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum

66 applications of complex plasmas hexamethyldisiloxane (HMDSO, C 6 H 18 Si 2 O) onto PE (model system) deposition of quartz-like films SiO x - barrier layers, protection - oxygen barriere binding energies: C-H 3,5eV; Si-C 4,6eV; Si-O 8,3eV CH 3 CH 3 + CH 3 Si O Si CH 3 CH 3 CH 3 Hexamethyldisiloxan PE PE (HMDSO, C6H 18Si2O) SiO x

67 polyethylene (PE): (C 2 H 4 ) n applications of complex plasmas hexamethyldisiloxane (HMDSO): C 6 H 18 Si 2 O Magni et al, J. Phys. D: Appl. Phys. 34 (2001) 87 Name H. Kersten des Vortragenden Progress Applications in Complex of Vortragstitel Dusty Plasma Plasmas Research Datum 06/23/ /05/2010

68 vessel applications of complex plasmas 3,4 cm chute 50 spiral cm 20 cm hollow cathode oscillation of electrons hollow cathode effect 1 Pam pd 50 Pam vibration motor H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum 06/23/2010

69 research activities reactive plasmas

70 reactive plasmas Silane Hydrocarbon Organo-silicone Silicon (Si) Diamond/DLC SiOx + Oxygen-containing plasmas J. Meichsner (Tue) H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum

71 J. Meichsner (Tue) Z. Donko (Wed) reactive plasmas CCP rf plasma

72 Sheath dynamics and excitation patterns in oxygen rf plasmas in experiment and simulations. 3 paper series in J. Phys. D. Appl. Phys. 40(2007), reactive plasmas J. Meichsner (Tue) S. Nemschokmichal (Tue) V. Shushkov (Tue) n e z/d 10ns 1µs 100µs z= 2.5 cm p= 100 Pa U= 550V 10ms z/d 10ms Spatio-temporaltemporal modelling of the ignition of abnormal oxygen glow discharge. IEEE Trans. Plasma Sci. 36(2008)992

73 reactive plasmas MW interferometry for negative ion diagnostics C. Küllig (Tue)

74 research activities microplasmas

75 microplasmas Challenge: Microplasmas n e (cm -3 ) ep Small dimensions Scaling laws Role of boundaries Surface charge & temperature Secondary species Quantum effects Discharge stability Operation modes K. Tachibana, Kyoto Plasma boundary physics Atmospheric pressure plasma Coupling of surface and volume processes

76 microplasmas surface barrier discharge G. Eden (Thu) V. Johnson (Thu) R. Foest (Thu)

77 microplasmas combination of vibrating device + planar DBD movement of powder particles original powders electrode (potential) ti 70 x 260 mm dielectric vibration ground plate and electrode 140 x 360 mm treated powders H. Kersten Progress in Complex Plasma Research 08/05/2010 Name des Vortragenden Vortragstitel Datum

78 R. Foest (Thu) microplasmas APPJ

79 L. Stollenwerk (Thu) microplasmas determination of surface charges

80 summary

81 summary Plasma size From large and stable plasmas to microplasmas. Plasma pressure From low pressure to atmospheric pressure. Plasma chemistry Time scales Correlations Quantum effects From simple gases to complex and reactive molecular plasmas and their interaction with condensed matter. From electron and ion dynamics to chemical reactions and collective behaviour of massive dust particles. Dynamics and thermodynamics of strongly correlated plasmas and particle clouds. Plasma boundary, plasma physics meets solid state physics.