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''Plasma Crystal''

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September 2009


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(Pictures courtesy of M. Kretschmer.
Click to enlarge.)

10 years of DLR parabolic flights: MPE takes part

Team The German Aerospace Center (DLR) celebrates 10 years of microgravity research onboard the Airbus A300 ZERO-G with its 14th parabolic flight campaign taking place in Cologne. The MPE takes part in this campaign, like already in 1999, with a complex plasma experi­ment conducted by U. Konopka, L. Wörner, M. Schwabe, Ch. Knapek, A. Lipaev (IHED/JIHT, Moscow), M. Kretschmer (see picture to the right), and G. Wildgruber (not in the picture). This campaign is situated at the airport Cologne (Köln-Bonn) for the forth time, adjacent to the DLR research center in Köln-Porz, and not in Bordeaux as usual where the aircraft is based. In an empty cargo building the scientists and engineers had two weeks time for the preparation of their experiments and to integrate them into the aircraft. The experiments were performed on three flight days.

The staff members of the MPE department ''Theory & Complex Plasmas'' tested a totally new plasma chamber, the so-called ''Zyflex'' chamber for the ''PlasmaLab'' project. This is a cylindrical high frequency plasma chamber with flexible geometry where e.g. the distance of the electrodes can be variied with integrated motors. The goal of ''PlasmaLab'' that is to follow the successful plasma experiment facilities ''PKE-Nefedov'' and ''PK-3 Plus'' onboard the International Space Station ISS is to expand the parameter range where complex plasmas can be studied in microgravity. More accurate and totally new results can be expected.

The predecessors of ''PlasmaLab'' (''PK-3 Plus'' and ''PK-4'', amongst others) have also been tested intensively on parabolic flights where each parabolic flight maneouver provides 20 seconds of weightlessness. ''PK-4'' is to be launched to the space station in 2011 and operated inside the European Columbus module. So, MPE personnel gained many years of experience in participation in parabolic flights. This time, two of them (Konopka, Kretschmer) were honoured with a bronze medal by Novespace, the aircraft owning company, for having completed more than 500 and 600, respectively, parabolas.

In addition to the usual three flight days with 31 parabolas MPE scientists were offered more flight opportunities on the two ''VIP'' campaign flight days with 10 parabolas each. Amongst other ''VIPs'' the German astronaut Thomas Reiter flew again into weightlessness. Reiter (51) spent several months onboard the Russian space station MIR and stayed onboard the ISS from July to December 2006 where he also operated our plasma crystal experiment twice. During the DLR parabolic flight campaign Thomas Reiter enjoyed operating MPE's next-generation plasma crystal experiment onboard the A300 ZERO-G.

On September 20 DLR organized an open aero-space day (''Tag der Luft- und Raumfahrt'') in the research center in Köln-Porz where 100,000 visitors took great interest in the research activities of DLR. Besides several research aircraft of DLR the Airbus A300 ZERO-G was on exhibition and MPE members informed the public about the plasma crystal experiment.

Captions (see left side, from top left to bottom):
The Airbus A300 ZERO-G arrives from Bordeaux in Cologne; PlasmaLab installed inside the Airbus; Open plasma chamber; Plasma chambe with mesh electrode; Thomas Reiter operates the PlasmaLab experiment; Airbus in the morning; Visitors line up the see the A300 and PlasmaLab on DLR's open day.

More links (external and mostly in German):
DLR: 14th DLR Parabolic Flight Campaign: List of Experiments, September 2009
DLR: More than 100,000 visitors at the DLR Open Day 2009
WDR: Schweben für die Wissenschaft

June 2009

PRL cover page
Cover page of ''Physical Review Letters'', Vol. 102, No.25 from 26 June 2009 (Enlarge)
Cover page of renowned journal ''Physical Review Letters'' from MPE

The cover of 26 June 2009 issue of the widespread journal ''Physical Review Letters'' shows a picture of an experiment conducted at the complex plasma group of the Max Planck Institute for extraterrestrial Physics by Mierk Schwabe. It depicts a microparticle droplet, which is formed in a complex plasma. Such a plasma consists of an ionized gas into which small charged particles - the microparticles - are inserted. Usually the particles are pulled to the lower part of the plasma inside the experimental chamber by gravity. If the bottom plate of the chamber is heated, they are lifted into the central part of the plasma. The resulting force compensates for gravity acting on the particles. The complex plasma then looks similar to those produced in analogous experiments with ''PK-3 Plus'', MPE's plasma lab in weightlessness onboard the International Space Station ISS. A central, particle free region is especially noticeable - the void.

Plasma Bubbles Under certain conditions novel phenomena appear at the lower boundary of this void under gravity conditions: Bubbles form, which ''explode'' upwards into the void, like shown on the picture to the right (Enlarge. Courtesy of M. Kretschmer). Droplets or blobs such as the one shown on the cover appear, ejecting particles into the void. Another phenomenon is the formation of cusps in the particle cloud, which are pointing upwards. These cones remind of so-called ''Taylor cones'', which form in liquids under the influence of electric fields and surface tension.

The picture on the cover demonstrates that the blobs were completely independent from the rest of the particle cloud. The illustration results from a tomographic procedure in which the droplet is recorded in vertical cuts that are later combined to a three-dimensional image.

Even though the droplets and bubbles contain only a few hundreds of particles, they demonstrate many effects typical for fluids. The particles inside the blobs move in vortices like in the case of water drops in an air stream, and there is evidence of surface tension. In contrast to water molecules, in complex plasmas the individual particles can be directly observed and examined. This makes complex plasmas the ideal model system for the dynamical analysis of such phenomena.

Reference: M. Schwabe, M. Rubin-Zuzic, S. Zhdanov, A. V. Ivlev, H. M. Thomas, and G. E. Morfill. Formation of Bubbles, Blobs, and Surface Cusps in Complex Plasmas, Physical Review Letters 102, 255005 (2009)

February 2009

MPE Parabolic Flight Team
MPE parabolic flight team, front: Christian Dey­sen­roth, Sebastian Albrecht, Michael Kretsch­mer. 2nd row: Markus Thoma, Hu­ber­tus Tho­mas, Mierk Schwa­be. Not on picture: Tanja Hagl, Ralf Heide­mann, Christian Rau.
Picture courtesy of M. Schwabe (Enlarge)

A300 Zero-G Picture
Airbus A300 Zero-G at Bordeaux airport.
Courtesy of M. Kretschmer (Enlarge)

DLR parabolic flight campaign #13: MPE contributes twice

On February 2 - 12 the 13th parabolic flight campaign organized by the German Aerospace Center (DLR) takes place in Bordeaux, France. And two of the selected experiments are proposed by the MPE: PK-4 und FAST PK-3 Plus.

PK-4 is the follow-up laboratory of the successful PK-3 Plus complex plasma facility that is onboard the International Space Station ISS since 2006. It is planned to be launched to the ISS in 2011 where it will be operated in the European "Columbus" module. PK-4 is designed to study complex plasmas in microgravity mainly in the fluid phase. At the time being the project is in phase c/d (supported by the European Space Agency ESA) which should lead to the first 1:1-model of the flight hardware. To check the microgravity capability of the components being built in several parabolic flight campaigns are necessary. Also scientific questions which can be answered in the 20 seconds duration of weightlessness in a parabola are planned. During one campaign 93 parabolas on 3 flight days are performed which leads to a cumulative zero-g time of 30 minutes. With PK-4 - on its 7th parabolic flight campaign - optimized gas jet dispensers are tested and self-organization effects in complex plasma fluids (so-called 'lane formation') are studied at this time.

FAST PK-3 Plus Logo Unlike PK-4, FAST PK-3 Plus (mission patch on right side; enlarge) makes its debut on this parabolic flight campaign. This experiment is based on the high frequency plasma chamber of PK-3 Plus, but in contrast to the ISS facility it is equipped with a fast video data acquisition system that allows the recording of images with 1 Mpixel resolution with 1000 frames per second. The big advantage of complex plasmas - that is to be able to simulate and observe condensed matter on individual particle ("atomic") level - can be exploited also for fast processes such as the transition of shock waves. The data acquisition system consists of a fast camera and a storage system made up by 24 hard disk drives which allow the recording of 30 minutes with the high frame rate. This sub-system alone weights around 75 kg which is as heavy as the whole facility in space. On parabolic flights with the Airbus A300 Zero-G plane the restrictions are less. Now the whole setup weights 370 kg which is quite normal for this kind of experiment.

During this parabolic flight campaign some PK-3 Plus experiments already performed onboard the ISS are repeated, but now with much higher visual and temporal resolution, for example, shock waves, self-excited waves, so-called 'string fluids' and 'thermophoretic bubbles'. The high speed recording allows also quick scans through the microparticles inside the plasma, so that we can even gain 3-dimensional information in liquid systems.

As usual the team stays 12 days in Bordeaux for setup integration, testing and the flight days. Again, our colleague Mierk Schwabe reports about the latest developments in Bordeaux and her first parabolic flight in her extblog. ('Wrap-up') (German only)

Marginal note: MPE staff member Michael Kretschmer, participating in parabolic flights since 2001, reaches his 500th parabola during this campaign. This is rewarded by the organizing company Novespace with a bronze medal.

January 2009

10th Mission Logo
PK-3 Plus 10th Mission Logo
(Enlarge) ©MPE/MK

3 years of PK-3 Plus: 10th Mission on ISS

In January MPE staff members visit the space control center in Moscow to conduct the 10th mission with the complex plasma experiment PK-3 Plus onboard the International Space Station ISS. Russian cosmonaut Yury Lonchakov - flight engineer of the 'Expedition 18' crew - will be available for our experiment on three days for 90 minutes each day.

PK-3 Plus is onboard the ISS since December 2005 and was operated for the first time in January 2006. So the 10th mission also marks the 3rd anniversary of this plasma facility in the microgravity environment of the space station. PK-3 Plus continues the successful story of the previous plasma laboratory PKE-Nefedov that was in orbit from 2001 until 2005 and was operated 13 times, making it one of the most used experiment facilities on the ISS.

This time experiments of crystallization, 'string fluids' and 'bubbles' are on the list. Bubbles inside a thermophoretic complex plasma were first discovered in the MPE in 2006 [1].

As in the former mission our colleague Mierk Schwabe will report in her extBlog about the latest events in Moscow. (German only!)

[1] M. Schwabe, et al: ''Formation of bubbles, blobs and surface cusps in fluid complex plasmas''. Submitted to Physical Review Letters, Dec. 2008

News 2008, 2007, 2006, 2005

Updated: 2010-02-02
Contact: Michael Kretschmer mail
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