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Complex Plasmas as a Model for the Quark-Gluon-Plasma Liquid

Complex Plasmas as a Model for the Quark-Gluon-Plasma Liquid. Markus H. Thoma * Max-Planck-Institute for Extraterrestrial Physics. Strongly Coupled Plasmas Complex Plasmas Applications to the Quark-Gluon Plasma. * Supported by DLR (BMBF). Strongly Coupled Plasmas.

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Complex Plasmas as a Model for the Quark-Gluon-Plasma Liquid

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  1. Complex Plasmas as a Model for the Quark-Gluon-Plasma Liquid Markus H. Thoma* Max-Planck-Institute for Extraterrestrial Physics • Strongly Coupled Plasmas • Complex Plasmas • Applications to the Quark-Gluon Plasma * Supported by DLR (BMBF)

  2. Strongly Coupled Plasmas Plasma = ionized gas, 99% of visible matter in Universe Plasmas generated by high temperatures, electric fields, or radiation • Classifications: • Non-relativistic – relativistic plasmas (pair plasmas, QGP) • Classical – quantum plasmas (white dwarfs, QGP) • Ideal – strongly coupled plasmas (complex plasmas, QGP)

  3. Coulomb coupling parameter Q: charge of plasma particles d: inter particle distance T: plasma temperature Ideal plasmas: G << 1 (most plasmas: G < 10-3) Strongly coupled plasmas: G > O (1) Examples: ion component in white dwarfs, high-density plasmas at GSI Non-perturbative description, e.g., molecular dynamics One-component plasma, pure Coulomb interaction (repulsive): G > 172 g Coulomb crystal

  4. Debye screeningg Yukawa systems Additional parameter:k = d/lD Liquid phase: G > O (1) Purely repulsive interaction g no gas-liquid transition, only supercritical fluid

  5. 2. Complex Plasmas Dusty or complex plasmas = multi component plasmas containing ions, electrons, neutral gas, and microparticles, e.g., dust Example: low temperature neon plasma in a dc- or rf discharge

  6. Injection of microparticles with diameter 1 – 10 mm High electron mobility g microparticles collect electrons on surface g large negative charge: Q = 103 – 105 e Inter particle distance about 200 mm g G >> 1 g plasma crystal (predicted 1986, discovered 1994 at MPE) Observation: illumination by laser sheet and recorded by CCD camera

  7. Melting of plasma crystal by • pressure reduction • less neutral gas friction gtemperature increase gdecrease of Coulomb coupling parameter G = Q2/(dT)

  8. Quantitive analysis of equation of state and determination of G: pair correlation function • Crystal: long range order • sharp peaks at the nearest neighbors, next to nearest neighbors and so on Liquid: short range order (incompressibility) gonly one clear peak corresponding to inter particle distance plus one or two broad and small peaks Gas: no order gno clear peaks

  9. Gravity has strong influence on microparticles gmicrogravity experiments

  10. Applications of complex plasmas: 1. Model system for phase transitions, crystallization, dynamical behavior of liquids and plasmas on the microscopic level 2. Astrophysics: comets, interstellar plasmas, star and planet formation, planetary rings, … 3. Technology: plasma coating and etching, e.g. microchip production, problem: dust contamination

  11. 3. Applications to the Quark-Gluon Plasma • Estimate of interaction parameter • C = 4/3(quarks), C = 3 (gluons) T = 200MeV g aS = 0.3 - 0.5 d = 0.5fm Ultrarelativistic plasma: magnetic interaction as important as electric • G = 1.5 – 6 gQGP Liquid? RHIC data (hydrodynamical description with small viscosity, fast thermalization) indicate QGP Liquid • Attractive and repulsive interaction g • gas-liquid transition at a temperature • of a few hundred MeV

  12. Static structure function (Fourier transform of pair correlation function) g experimental and theoretical analysis of liquids Hard Thermal Loop approximation (T >> Tc): • interacting gas QCD lattice simulations g QGP liquid?

  13. Strongly coupled plasmas g cross section enhancement • Reason:Coulomb radius, rC = Q2/E,larger than Debye screening length • lD = 1/mDg modification of Coulomb scattering theory • g enhancement of ion-microparticle interaction (ion drag force) • QGP: rC /lD = 1 – 5 g parton cross section enhancement by factor 2 – 9 • small mean free path l(corresponding to small viscostity h ~ l) and fast • thermalization. • Additional cross section enhancement by non-linear and non-perturbative • effects Implication: enhancement of collisional energy loss, suppression of radiative energy loss by LPM effect (formation time) g jet quenching

  14. Conclusions • Strongly coupled plasmas are of increasing importance in • fundamental research as well as technology • QGP and complex plasmas are important examples of strongly • coupled plasmas • QGP is the most challenging strongly coupled plasma • Complex plasmas can easily be studied and used as a model • for the QGP (phase transitions, correlation functions, cross sections, …) • RHIC and ISS provide very important information on strongly coupled • plasmas

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