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Title: Langmuir probe system for dusty plasmas under microgravity

Abstract

This article describes a fully automated 2D-scanning Langmuir probe system for dusty plasmas under microgravity. The design combines necessary features such as random sampling, radio frequency compensation, and a compact mechanical design. The various aspects of the probe implementation and the contamination problem in the dusty plasma environment are discussed and the functionality of the system is demonstrated by measurements performed on parabolic flights.

Authors:
; ;  [1]
  1. Institut fuer Experimentelle und Angewandte Physik, Christian-Albrechts-Universitaet Kiel, 24098 Kiel (Germany)
Publication Date:
OSTI Identifier:
20953387
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 78; Journal Issue: 3; Other Information: DOI: 10.1063/1.2714036; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; DESIGN; IMPLEMENTATION; LANGMUIR PROBE; PLASMA; RADIOWAVE RADIATION; SAMPLING; WEIGHTLESSNESS

Citation Formats

Klindworth, M., Arp, O., and Piel, A. Langmuir probe system for dusty plasmas under microgravity. United States: N. p., 2007. Web. doi:10.1063/1.2714036.
Klindworth, M., Arp, O., & Piel, A. Langmuir probe system for dusty plasmas under microgravity. United States. doi:10.1063/1.2714036.
Klindworth, M., Arp, O., and Piel, A. Thu . "Langmuir probe system for dusty plasmas under microgravity". United States. doi:10.1063/1.2714036.
@article{osti_20953387,
title = {Langmuir probe system for dusty plasmas under microgravity},
author = {Klindworth, M. and Arp, O. and Piel, A.},
abstractNote = {This article describes a fully automated 2D-scanning Langmuir probe system for dusty plasmas under microgravity. The design combines necessary features such as random sampling, radio frequency compensation, and a compact mechanical design. The various aspects of the probe implementation and the contamination problem in the dusty plasma environment are discussed and the functionality of the system is demonstrated by measurements performed on parabolic flights.},
doi = {10.1063/1.2714036},
journal = {Review of Scientific Instruments},
number = 3,
volume = 78,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
  • Structure formation of dust particles in dusty plasmas under microgravity has been simulated by the molecular dynamics method. It is shown that, at low temperatures, dust particles are organized into layered spherical shells. The number of shells is a function of the system size and the strength of screening by ambient plasma particles, while the dependency on the latter is much weaker. In the simulation, the condition of the charge neutrality satisfied by the system of dust particles and plasma particles is properly taken into account.
  • Experiments in a dusty plasma under the microgravity conditions of parabolic flights are presented. Under microgravity, extended dust structures and a central dust-free region ('void') are formed. Here, the forces and the force balance at the void boundary are studied by means of laser manipulation of the dust particles: A focused laser beam is moved in a controlled way to drive particles in the extended dust cloud and at the void boundary. From the observed particle motion, the forces on the particles in the dust cloud and at the void boundary are derived. Together with Langmuir probe measurements, a quantitativemore » description of the force balance has been achieved. Special attention has been paid to the ion drag force, which is crucial in understanding the void formation. The results are compared to prevalent ion drag models.« less
  • A three-camera stereoscopy setup is presented that allows to reconstruct the trajectories of particles in dusty plasmas under microgravity. The calibration procedure for the three-camera setup takes the special circumstances into account that occur in close-range imaging of small particles. Additionally, a reconstruction algorithm is presented that is based on the epipolar geometry and delivers the essential particle correspondences. Further improvements are achieved by analyzing the dynamic particle behavior. Two applications of our calibration and reconstruction procedure are presented: A two-dimensional dust structure in the laboratory with a large percentage of hidden particles, and particles inside the void of amore » dust cloud under microgravity.« less
  • In present experiment an ordering and dynamics of monodisperse nylon rods (D = 10 {mu}m, L = 300 {mu}m) in a uniform DC gas discharge plasma under microgravity have been investigated. Ordered rod structures were registered in DC discharge with a rod concentration of 400-8000 cm{sup -3} and a neon pressure range of 20-50 Pa. The structures revealed orientationally ordered hexagonal structures. DC discharge became unstable at rod number density more then 8000 cm{sup -3}. Rod drift velocities in a permanent electric field were measured for the neon pressure range. Dust acoustic instability ({nu}{approx}0.4{+-}0.1 Hz, {lambda}{approx}1.1{+-}0.4 cm, C{sub DAW}{approx}0.5 cm/s)more » in rod cloud was observed at a neon pressure of 25 Pa and a rod number density of 1500 cm{sup -3}. Using the 'low' frequency approximation of the linearized DAW dispersion relation and the measured rod drift velocity a rod electric charge had been estimated as Z{sub R}{approx}150000e.« less
  • The penetration of a dusty plasma by fast charged projectiles is studied under microgravity conditions. The mass and charge of the projectiles are larger than those of the target particles. A projectile generates a dust-free cavity in its wake, whose shape strongly depends on the projectile velocity. The faster the projectile the more elongated becomes the cavity while its cross-section decreases. The opening time of the cavity is found independent of the projectile velocity. For supersonic projectiles, the dynamics of the cavity can be decomposed into an initial impulse and a subsequent elastic response that can be modeled by amore » damped harmonic oscillator.« less