..(1), ..(1), ..(1), ..(1), ..(2), ..(2), ..(2), ..(2), ..(3), ..(3), ..(3), ..(4), .(5)(1) , , (2) . , , (3)-, , (4) . .. , , (5) , ,

, , 27 2008

OutlineScience Goals of PK-3 PlusPK-3 Plus experimental setupResults:Electrorheological plasmas string fluid formationTwo phase flow lane formation3D phase transition crystal liquidConclusion

PK-3 Plus Science GoalsOrdered structures in 3D complex plasma in a weak electric fieldCrystal-liquid-gas phase transitions in 3D isotropic complex plasma systemStructural phase transitions in 3D complex plasma under external actionsLinear and nonlinear waves in 3D complex plasma including shock waves, instabilitiesTransport of microparticlesBoundaries in complex plasmasDecharging

The Plasma ChamberHigh homogeneity of plasma parameters due to electrodes designPerfect observation conditions due to glass wallsHigh homogeneity of temperature due to construction design2D3D13.56 Mhz RF power driven large disk electrodesWide ground rings around the electrodesGuard rings hold 3 dispensers eachThe dispensers provide 14.91; 9.19; 6.81; 3.42; 2.55 m melamine formaldehyde and 1.55 m silica mono disperse particles

PK-3 Plus hardware turbomolecular pump inside the container provides HV conditions in the 10-6 mbar rangecontinuous gas flow for stable high purity gas conditionspressure control baratron, piezo, pirani2 gas reservoirs filled with Ar and NeRF control voltage, current (measured on electrodes)function generator 0 255 Hz, -55V +55 drives electrodes independently with sinusoidal, square, triangle etc. shapes4 progressive scan cameras (up to 50 Hz frame rate)horizontal translation stagevertical translation stagedigital storage of 4 analogue video signals on hard disks

Laboratory Onboard Accommodationexperiment hardware enveloped in safety housing and connected to outside prevacuum port at transfer compartmenttelescience unit includes ruggedized laptop and 4 digital video recordersLCD video monitor allows control by operatorPK-3 Plus, Yu. Malenchenko (2008)

Electrorheological plasma PK-3 Plus, Th. Reiter (2006)At zero field particles interact via classic Debye-Hckel potentialIon drift generates the positive ion wakeThe ac field Eext with frequency f: fdust

Kinetics of strings formationPK-3 Plus, F. Yurchihin (2006)Time of string fluid recreation is about 15 seconds

Two phase flowDispensers test : 14.9, 9.2, 6.8, 3.4, 2.5, 1.5 m particles diameterPK-3 Plus, V. Tokarev (2006)

Colloids Lane FormationStrongly interacting colloidal mixture consisting of oppositely driven particlesNonequilibrium transition towards lane formation (Rayleigh-Taylor instability)Lane formation is a generic process and occurs:Colloidal suspensionsIons migrating within 2D membranesPedestrian zonesComplex plasmas

J. Chakrabarti et al., PHYSICAL REVIEW E 70, 012401 (2004)force

Quasi continuous flowPK-3 Plus, Yu. Malenchenko (2007)

Reentrance effect in complex plasma lanesJ. Chakrabarti et al., PHYSICAL REVIEW E 70, 012401 (2004)lane formation experiments were made at different conditionsincreasing interaction potential prevents lane formation

Penetration of 1.55m particles through 2.55m particles cloud

Crystal-Liquid Phase TransitionThe plasma crystal in ground lab melts while pressure decreasesThe plasma crystal in space lab melts while pressure increasesPK-3 Plus, Yu. Malenchenko (2007)P=13.6 Pa (pressure decreases)P=11.3 Pa (pressure minimum)P=14.7 Pa (pressure increases)P=20.9 Pa (pressure maximum)

Crystal1.55 m grainsArgon pressure 11.7 PaFrame size 8136 x 5932.8 mLiquid1.55 m grainsArgon pressure 21.1 PaFrame size 8136 x 5932.8 mWithout external fieldPair distribution function g(r)Dependences of K and pressure on timeK=g(rmin)/g(rmax) =0.2 - crystallization pointFrenkel & McTague Ann.Rev.Phys.Chem. 1980

Phase diagram

Phase transition search for 2.55m particles cloud

Crystal1.55 m grainsArgon pressure 11.3 PaFrame size 8136 x 5932.8 mLiquid1.55 m grainsArgon pressure 21 PaFrame size 8136 x 5932.8 mWith low frequency external field (255Hz)Dependences of K and pressure on timePair distribution function g(r)K= 0.2 - crystallization pointFrenkel & McTague Ann.Rev.Phys.Chem. 1980

ConclusionsThe experiments with PK-3 Plus show the perfect functioning of the apparatusStructural phase transition was discoveredLane formation was investigated at different complex plasma parametersCrystal-liquid phase transition was obtained in large 3D isotropic complex plasma systemPK-3 Plus provides much better insights into the properties of complex plasmas

MPE and IHED scientific teams are very much appreciated to all specialists from DLR, Roscosmos, RSCE Energia, Gagarin Cosmonaut Training Centre, Moscow Mission Control Centre, Kayser-Threde who made possible Plasma Crystal experiments.Very special thanks to cosmonauts who made the decisive steps in the experiments realization from January 1998

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