Hubertus M. Thomas

Center for Astrophysics Harvard & Smithsonian

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Co-Authors

Markus H. Thoma

University of Giessen

207

P. K. Shukla

University of California, Santa Barbara

163

Vladimir Yu. Nosenko

Peninsula Library System

150

G. E. Morfill

Max Planck Society

133

A. M. Lipaev

Joint Institute for High Temperatures

126

V. I. Molotkov

Joint Institute for High Temperatures

118

A. V. Ivlev

Max Planck Institute for Extraterrestrial Physics

117

ВЕ

В. Е. Фортов

Joint Institute for High Temperatures

V. Nosenko

Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)

ОФ

О. Ф. Петров

Joint Institute for High Temperatures

Cooperative Institutions

Max Planck Society

123

Max Planck Institute for Extraterrestrial Physics

118

Joint Institute for High Temperatures

Centre National de la Recherche Scientifique

Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)

Russian Academy of Sciences

Moscow Institute of Physics and Technology

Auburn University

Gagarin Research and Test Cosmonaut Training Center

Kiel University

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Reasons Why We Need Cold Atmospheric Plasmas in Bacteria-Related Diseases in Medicine

Plasma Medicine (2012)

Georg Isbary Julia Zimmermann Tetsuji Shimizu G. E. Morfill Anindita Mitra

Upcoming technologies for medical purposes must demonstrate their unique features and benefits compared with other methods in use. Cold atmospheric plasma technology has unique properties regarding antimicrobial purposes, owing to the numerous ways to generate and design the plasma. To date, no primary resistance against any tested microbes has been found. Furthermore, several tests and theoretical calculations show the unlikelihood of microbes acquiring resistance against cold atmospheric plasma. The latter fact is the main advantage of cold atmospheric plasma technology compared with conventional antimicrobial products (e.g., antibiotics) available in the medical sector, whose more or less uncontrolled usage has led to global resistance concerns and possibly to a lack of future treatment approaches.

10.1615/plasmamed.2014006273

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Citations (7)

Pulsed rf-Discharge in Zyflex-Chamber

Peter Huber Christina A. Knapek Daniel Mohr Erich Zähringer Hubertus M. Thomas

Interrupting rf-discharge is a well known method to control processes in plasmas. For example in semiconductor processing, it can be used to control growth of particles from material out of the plasma phase. By switching of the discharge, grown fog can be driven out of the plasma by gravity. [2] On the other hand, pulsing the plasma gives a good possibility to tune effective electron temperature independently from plasma density. This way you could tune parameters in complex plasma systems like electron density, electron temperature, screening length and particle charge in a more flexible way. Ekoplasma is a project designing the future lab for complex plasma research on the inter- national space station ISS. Together with its large cylindrical chamber Zyflex it will have many features to cover a wide range of physics in complex plasma research, now to be tested in lab and on parabolic flights. It also includes a multifunctional rf-generator which can be pulsed at different frequencies with on/off times even down to 50 µs. Combining this switching features with micro gravity conditions it will be possible to tune plasma parameters without loosing particles due to gravity pushing the particles. In this contribution, we show the plasma pulsing feature of the current lab setup of EkoPlasma and some first results from lab experiments.

Electron temperature

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Autowaves in a dc complex plasma confined behind a de Laval nozzle

EPL (Europhysics Letters) (2013)

Martin Fink S. K. Zhdanov Mierk Schwabe Markus H. Thoma H. Höfner

Experiments to explore stability conditions and topology of a dense microparticle cloud supported against gravity by a gas flow were carried out. By using a nozzle-shaped glass insert within the glass tube of a dc discharge plasma chamber a weakly ionized gas flow through a de Laval nozzle was produced. The experiments were performed using neon gas at a pressure of 100 Pa and melamine-formaldehyde particles with a diameter of 3.43 μm. The capturing and stable global confining of the particles behind the nozzle in the plasma were demonstrated. The particles inside the cloud behaved as a single convection cell inhomogeneously structured along the nozzle axis in a tube-like manner. The pulsed acceleration localized in the very head of the cloud mediated by collective plasma-particle interactions and the resulting wave pattern were studied in detail.

Particle (ecology)

Glass tube

10.1209/0295-5075/102/45001

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Citations (16)

Critical Point in Complex Plasmas

Physical Review Letters (2006)

S. A. Khrapak G. E. Morfill A. V. Ivlev Hubertus M. Thomas D. Beysens

The occurrence of liquid-vapor phase transition and the possible existence of a critical point in complex plasmas---systems that consist of charged micrograins in a neutralizing plasma background---is investigated theoretically. An analysis based on the consideration of the intergrain interaction potential suggests that under certain conditions systems near and at the critical point should be observable. Measurements under microgravity conditions would appear to be required. The analysis aims at determining the plasma parameter regime most suitable for planned experimental investigations.

Critical point (mathematics)

10.1103/physrevlett.96.015001

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Citations (58)

Self-propelled motion of an extra particle in a two-dimensional plasma crystal

Ingo Laut Christoph Räth S. Zhdanov V. Nosenko Gregor E. Morfill

Plasma crystals consist of charged microparticles that levitate in a weakly ionized gas. In these nonequilibrium systems the particle interaction is nonreciprocal due to flowing ions. Plasma crystals were successfully used to study dynamical effects in liquids and solids at the kinetic level and have the potential to also enable the study of active particles. Here, we analyze in simulations and theory the self-propelled motion of an particle in a two-dimensional plasma crystal. Experimental observations [1] showed that the extra particle is confined in a channel of two neighboring rows of particles and moves persistently through the crystal. We use the simple model of a pointlike ion wake charge to reproduce this intriguing effect in simulations. We show that the nonreciprocity of the particle interaction, owing to the plasma flow, is responsible for a broken symmetry of the channel that enables the self-propelled motion of the extra particle [2]. [1] C.-R. Du, V. Nosenko, S. Zhdanov, H. M. Thomas, and G. E. Morfill, Phys. Rev. E 89, 021101(R) (2014) [2] I. Laut, C. Rath, S. K. Zhdanov, V. Nosenko, G. E. Morfill, and H. M. Thomas, accepted for publication in Phys. Rev. Lett.

Particle (ecology)

Magnetosphere particle motion

Crystal (programming language)

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Removing dust particles from a large area discharge

Applied Physics Letters (2009)

Yang‐Fang Li Uwe Konopka Ke Jiang Tetsuji Shimizu H. Höfner

Introducing a striped electrode in a large area discharge allows us to transport microparticles in the discharge in a user defined way. A directed and continuous dust transport is established by modulating the voltage signals on all individual electrodes to cause a traveling plasma sheath distortion. Particles, trapped in the potential wells and thus following the distortions, are finally removed from the central discharge region. Transport efficiency and velocity can be controlled by changing amplitude and traveling velocity of the plasma distortions.

Distortion (music)

10.1063/1.3089873

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Citations (18)

Electrode Configuration for Dusty Plasmas with Uniform Dust Clouds under Microgravity Conditions

AIP conference proceedings (2011)

Kazuo Takahashi Noriyoshi Sato Yukio Watanabe Yasuaki Hayashi Satoshi Adachi

The dusty (complex) plasma research project is going on with cooperation for the PK‐3 plus flight module between scientific teams of Germany and Russia. Uniformities of plasmas and dust particle distributions are significant in the project and future works to understand physical phenomena in dust clouds. The present work shows dust particle distributions can be changed by modification of an electrode, implying changing plasma space potential profiles.

Dusty plasma

Particle (ecology)

10.1063/1.3659822

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Collective Effects in Vortex Movements in Complex Plasmas

Physical Review Letters (2014)

Mierk Schwabe S. Zhdanov Christoph Räth David B. Graves Hubertus M. Thomas

We study the onset and characteristics of vortices in complex (dusty) plasmas using two-dimensional simulations in a setup modeled after the PK-3 Plus laboratory. A small number of microparticles initially self-arranges in a monolayer around the void. As additional particles are introduced, an extended system of vortices develops due to a nonzero curl of the plasma forces. We demonstrate a shear-thinning effect in the vortices. Velocity structure functions and the energy and enstrophy spectra show that vortex flow turbulence is present that is in essence of the "classical" Kolmogorov type.Received 12 August 2013DOI:https://doi.org/10.1103/PhysRevLett.112.115002© 2014 American Physical Society

10.1103/physrevlett.112.115002

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Citations (55)

Role of Magnetic Field on Dust Crystal Formation

AIP conference proceedings (2011)

Nilakshi Das S. Baruah Vladimir Yu. Nosenko P. K. Shukla Markus H. Thoma

Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation Nilakshi Das, Swati Baruah; Role of Magnetic Field on Dust Crystal Formation. AIP Conf. Proc. 29 November 2011; 1397 (1): 451–452. https://doi.org/10.1063/1.3659888 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAIP Publishing PortfolioAIP Conference Proceedings Search Advanced Search |Citation Search

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10.1063/1.3659888

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Surface waves and resonances in magnetized plasmas with positive and negative dust grains or nanoparticles

AIP conference proceedings (2011)

N. F. Cramer Vladimir Yu. Nosenko P. K. Shukla Markus H. Thoma Hubertus M. Thomas

Magnetized plasmas with oppositely charged dust grains can exist in laboratory or space environments, as can oppositely charged nanoparticles such as Fullerenes. Such plasmas are spatially structured, with sharp or diffuse boundaries, and ocalized surface wave modes can exist near the interface of the plasma with the adjoining medium. Resonances and cutoffs of the waves can occur in the structured surface, which can lead to wave energy absorption and wave damping. Such plasmas can show distinctive features, analogous to pair plasmas, in particular Alfvén resonance absorption.

Dusty plasma

10.1063/1.3659805

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