Role of tunneling in electron accretion on negatively charged dust particles

2010 ◽  
Vol 374 (34) ◽  
pp. 3376-3379 ◽  
Author(s):  
M.S. Sodha ◽  
S.K. Mishra ◽  
Shikha Misra
Keyword(s):  
Dust Particles ◽  
Charged Dust

Dust vortices in a direct current glow discharge plasma: a delicate balance between ion drag and Coulomb force

2019 ◽  
Vol 85 (1) ◽  
Author(s):  
Sayak Bose ◽  
M. Kaur ◽  
P. K. Chattopadhyay ◽  
J. Ghosh ◽  
Edward Thomas ◽  
...  
Keyword(s):  
Glow Discharge ◽  
Discharge Current ◽  
Discharge Plasma ◽  
Coulomb Force ◽  
Plasma Potential ◽  
Glow Discharge Plasma ◽  
Dust Particles ◽  
Charged Dust ◽  
Surface Evolution

Dust vortices with a void at the centre are reported in this paper. The role of the spatial variation of the plasma potential in the rotation of dust particles is studied in a parallel plate glow discharge plasma. Probe measurements reveal the existence of a local potential minimum in the region of formation of the dust vortex. The minimum in the potential well attracts positively charged ions, while it repels the negatively charged dust particles. Dust rotation is caused by the interplay of the two oppositely directed ion drag and Coulomb forces. The balance between these two forces is found to play a major role in the radial confinement of the dust particles above the cathode surface. Evolution of the dust vortex is studied by increasing the discharge current from 15 to 20 mA. The local minimum of the potential profile is found to coincide with the location of the dust vortex for both values of discharge currents. Additionally, it is found that the size of the dust vortex as well as the void at the centre increases with the discharge current.

Antiprobcotron magnetic trap for charged dust particles in space experiments

2019 ◽  
pp. 20-29
Author(s):  
Lev G. D’YACHKOV ◽  
Mikhail M. VASILYEV ◽  
Oleg F. PETROV ◽  
Sergey F. SAVIN ◽  
Igor V. CHURILO
Keyword(s):  
Magnetic Trap ◽  
Space Station ◽  
Coulomb Systems ◽  
Inhomogeneous Magnetic Field ◽  
Dust Particles ◽  
Charged Dust ◽  
Magnetic Traps ◽  
Space Experiments ◽  
Microgravity Conditions ◽  
New Space

We discuss the possibility of using static magnetic traps as an alternative to electrostatic traps for forming and confining structures of charged dust particles in a gas discharge plasma in the context of our study of strongly interacting Coulomb systems. Some advantages of confining structures in magnetic traps over electrostatic ones are shown. Also we provide a review of the related researches carried out first in laboratory conditions, and then under microgravity conditions including the motivation of performing the experiments aboard the International Space Station (ISS). The preparations of a new space experiment «Coulomb-magnet» as well as the differences of a new equipment from previously used are described. We proposed the main tasks of the new experiment as a study of the dynamics and structure of active monodisperse and polydisperse macroparticles in an inhomogeneous magnetic field under microgravity conditions, including phase transitions and the evolution of such systems in the kinetic heating of dust particles by laser radiation. Key words: Coulomb structures, magnetic trap, antiprobotron, diamagnetic particles, dust particles, microgravity.

scholarly journals A new method of inferring the size, number density, and charge of mesospheric dust from its in situ collection by the DUSTY probe

2019 ◽  
Vol 12 (3) ◽  
pp. 1673-1683 ◽  
Author(s):  
Ove Havnes ◽  
Tarjei Antonsen ◽  
Gerd Baumgarten ◽  
Thomas W. Hartquist ◽  
Alexander Biebricher ◽  
...  
Keyword(s):  
New Method ◽  
Production Model ◽  
Dust Particles ◽  
Bottom Plate ◽  
Charged Dust ◽  
Fundamental Parameters ◽  
Dust Charge ◽  
Analysis Technique ◽  
June July ◽  
The Impact

Abstract. We present a new method of analyzing measurements of mesospheric dust made with DUSTY rocket-borne Faraday cup probes. It can yield the variation in fundamental dust parameters through a mesospheric cloud with an altitude resolution down to 10 cm or less if plasma probes give the plasma density variations with similar height resolution. A DUSTY probe was the first probe that unambiguously detected charged dust and aerosol particles in the Earth's mesosphere. DUSTY excluded the ambient plasma by various biased grids, which however allowed dust particles with radii above a few nanometers to enter, and it measured the flux of charged dust particles. The flux measurements directly yielded the total ambient dust charge density. We extend the analysis of DUSTY data by using the impact currents on its main grid and the bottom plate as before, together with a dust charging model and a secondary charge production model, to allow the determination of fundamental parameters, such as dust radius, charge number, and total dust density. We demonstrate the utility of the new analysis technique by considering observations made with the DUSTY probes during the MAXIDUSTY rocket campaign in June–July 2016 and comparing the results with those of other instruments (lidar and photometer) also used in the campaign. In the present version we have used monodisperse dust size distributions.

Future lunar missions and investigation of dusty plasma processes on the Moon

2013 ◽  
Vol 79 (4) ◽  
pp. 405-411 ◽  
Author(s):  
SERGEY I. POPEL ◽  
LEV M. ZELENYI
Keyword(s):  
Dusty Plasma ◽  
Lunar Surface ◽  
Dust Particles ◽  
Maximum Height ◽  
Charged Dust ◽  
The Moon ◽  
Plasma System ◽  
Lunar Dust ◽  
The Impact ◽  
Dusty Plasma System

AbstractFrom the Apollo era of exploration, it was discovered that sunlight was scattered at the terminators giving rise to “horizon glow” and “streamers” above the lunar surface. Subsequent investigations have shown that the sunlight was most likely scattered by electrostatically charged dust grains originating from the surface. A renaissance is being observed currently in investigations of the Moon. The Luna-Glob and Luna-Resource missions (the latter jointly with India) are being prepared in Russia. Some of these missions will include investigations of lunar dust. Here we discuss the future experimental investigations of lunar dust within the missions of Luna-Glob and Luna-Resource. We consider the dusty plasma system over the lunar surface and determine the maximum height of dust rise. We describe mechanisms of formation of the dusty plasma system over the Moon and its main properties, determine distributions of electrons and dust over the lunar surface, and show a possibility of rising dust particles over the surface of the illuminated part of the Moon in the entire range of lunar latitudes. Finally, we discuss the effect of condensation of micrometeoriod substance during the expansion of the impact plume and show that this effect is important from the viewpoint of explanation of dust particle rise to high altitudes in addition to the dusty plasma effects.

Role of neutral-particle bombardment in dust–dust interactions in plasmas

2001 ◽  
Vol 65 (4) ◽  
pp. 257-272 ◽  
Author(s):  
Ya. K. KHODATAEV ◽  
G. E. MORFILL ◽  
V. N. TSYTOVICH
Keyword(s):  
Free Path ◽  
Particle Bombardment ◽  
Neutral Particle ◽  
Mean Free Path ◽  
Dust Particles ◽  
Neutral Particles ◽  
Additional Force ◽  
Numerical Coefficient ◽  
The Mean

It is shown that the interaction of dust with neutral plasma particles can lead to attractive forces between dust particles, both in the case where the distance between dust particles is less than the mean free path of neutral particles and in the case where it is greater. The expressions for attractive forces differs in the two limits only by a numerical coefficient. The additional force of dust interaction is found to be due to the neutrals created by recombination of charged plasma particles on the surface of dust particles. The influence of radiative dust cooling on dust–dust interaction is considered.

scholarly journals Electrostatic Analyses for a System Constituted by an Insulating Disk Whose One Plane Surface is Charged and Which is Backed by a Concentric Earthed Metal Disk Smaller Than the Insulating Disk Itself and an Earthed Sphere Approaching the Charged Surface of the Insulating Disk, and Its Application to the Case of a Typical Oxygen Regulator

2019 ◽  
Author(s):  
Nirmalya Basu
Keyword(s):  
Electric Field ◽  
Plane Surface ◽  
Dust Particles ◽  
Charged Dust ◽  
Potential Candidate ◽  
Charged Surface ◽  
Electrostatic Discharges ◽  
Valve Stem ◽  
Metal Disk ◽  
Metal Diaphragm

There is a proposition that the possible occurrence of electrostatic discharges inside an oxygen regulator between charged insulating components, such as diaphragms, and earthed metal components, such as the valve stem, could be a potential candidate responsible for oxygen regulator fires. In this paper, the electric field which might be produced at the tip of the valve stem due to charge produced on the diaphragm of a typical oxygen regulator by deposition of charged dust particles or by their impact on the diaphragm or both has been evaluated. The diaphragm, in many cases, is backed partially by a concentric earthed metal disk. The diaphragm has been modelled as an insulating disk. The tip of the valve stem has been modelled as an earthed sphere which is very small compared to the insulating disk and the backing earthed metal disk. An analytical expression for the electric field produced at the point of the sphere nearest to the charged surface of the insulator has been derived. Our expression takes into account not only the effect of the charge on the insulating disk, but also that due to the presence of the backing earthed metal disk. Results for the magnitude of this electric field have been computed for the case of a sample oxygen regulator. An expression for the critical charge density on the surface of the insulating disk has been derived, and its value has been obtained for the case of our sample oxygen regulator. The electric field inside the non-metal diaphragm has also been evaluated. It appears from our analyses that there is a possibility that an electrostatic discharge might occur inside an oxygen regulator, and with an enriched-oxygen atmosphere being present there, such a discharge could also lead to a fire incident.

scholarly journals The role of physical activity on blood factors, lipid profile, and liver enzymes of tile factory workers (A Case Study)

2020 ◽  
Author(s):  
MH Dashti khavidaki ◽  
AA Minaeifar ◽  
F Rassekh ◽  
A Baghiani
Keyword(s):  
Physical Activity ◽  
Lipid Profile ◽  
Liver Enzymes ◽  
Venous Blood ◽  
Dust Particles ◽  
Factory Workers ◽  
Cross Sectional ◽  
Tile Factory ◽  
Blood Factors

Introduction: Inhalation of dust particles is prone to chronic diseases, and regular exercise reduces the risk of cardiovascular disease and improves blood variables. The purpose of this study was to investigate the role of physical activity on blood factors, lipid profile, and liver enzymes in tile factory workers. Materials and Methods: This is a cross-sectional study. 70 workers who were eligible to participate in the study were selected based on the sampling method available at the workplace. According to the Beck questionnaire, 15 people were included in each active and inactive groups. After 12 hours of worker's last meal, 10 ml of venous blood was used to evaluate biochemical variables of Blood factors (RBC, Hematocrit, Hemoglobin, WBC), lipid profile (Cholesterol, Triglyceride). Liver enzyme (ALT, AST, ALP) tests of both groups were performed in the occupational medicine laboratory of Meybod city, and SPSS Ver.23 software was used for analysis. Results: The results showed that red blood cells (p = 0.003) and hemoglobin (p = 0.034) in the active group were significantly higher than the inactive group. Also triglyceride (p = 0.025) and cholesterol (p = 0.042) of liver enzymes, (p = 0.011) ALT and AST (p = 0.047) were significantly lower. Conclusion: It seems that physical activity can have a positive effect; it can improve blood factors, liver enzymes, and fat profile in workers. According to the results, tile factory workers can achieve the desired blood factors with minimal physical activity.

scholarly journals Physical Processes in Cometary Atmospheres

1972 ◽  
Vol 45 ◽  
pp. 253-259 ◽  
Author(s):  
A. Z. Dolginov
Keyword(s):  
Rotation Period ◽  
Dust Particles ◽  
Molecular Flow ◽  
Physical Parameters ◽  
Charged Dust ◽  
Nuclear Surface ◽  
Cometary Dust ◽  
Meteor Streams ◽  
Cometary Tail ◽  
Dust Component

Formulae are obtained for the distribution of molecules in the cometary head, taking into account the conditions of hydrodynamic and free molecular flow in various regions around the nucleus. Experimental data are used to derive physical parameters near the nuclei of comets 1952 III, 1955 V, 1957 III, and 1960 II and the rate of decrease of mass. The possibility of chemical reactions in the region close to the nucleus is discussed. Gas condensation is shown to be a possible cause of dust formation under the conditions existing near the nucleus, and this process may be responsible for the major portion of the cometary dust component. The observed grouping of synchrones in the cometary tail can be explained on the assumption that the nuclear surface comprises two (or more) areas differing essentially in evaporation rate, the amount of matter ejected varying over the rotation period of the nucleus. Charged dust particles are shown to form, with electrons and ions, a common medium, i.e., dust plasma, which can be treated by the same methods used for ordinary plasma. Special investigations appear to be desirable when comets intersect meteor streams.

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