On the disturbance caused by a stationary dust grain in a flowing plasma

2005 ◽  
Author(s):  
N. Arinaminpathy
Keyword(s):  
Flowing Plasma ◽  
Dust Grain ◽  
Stationary Dust

Complex charge distributions of dielectric dust grains due to plasma flow

2000 ◽  
Vol 63 (3) ◽  
pp. 269-283 ◽  
Author(s):  
J. W. MANWEILER ◽  
T. P. ARMSTRONG ◽  
T. E. CRAVENS
Keyword(s):  
Charge Distribution ◽  
Large Fraction ◽  
Dusty Plasmas ◽  
Young Stars ◽  
Dust Particles ◽  
Total Charge ◽  
Dust Grains ◽  
Charge Distributions ◽  
Flowing Plasma ◽  
Dust Grain

We examine the charging of dielectric dust grains embedded in a plasma. Our work is a continuation and refinement of our previous research into grain charging problems. In 1993, we discussed preliminary simulation results regarding the charging and intergrain forces between two dielectric dust particles [J. W. Manweiler et al., Adv. Space Res. 13, 10175 (1993)]. Then, in 1996, we discussed preliminary results with respect to dust grain charging within asymmetric plasma conditions and how these affect grain–grain collisional cross-sections [J. W. Manweiler et al., In: The Physics of Dusty Plasmas (ed. P. K. Shukla et al.), p. 22. World Scientific, Singapore (1996)]. This work was extended to evaluate how asymmetric charging affects coagulation rates for dielectric dust grains [J. W. Manweiler et al., In: Physics of Dusty Plasmas, 7th Workshop (ed. M. Horanyi et al.), p. 12. AIP Conf. Proc. 446 (1998)]. Here we report on the results of a significant refinement to our work to study the behaviour of a dielectric dust grain in a plasma with a bulk flow. Since charge transport is inhibited on our dielectric grains, we can examine how asymmetric plasma distributions affect the symmetry of the charge distributions that develop on the surfaces of the grains. A dielectric dust grain in a flowing plasma develops a negative total charge and a dipole moment in its charge distribution that points upstream. We also use this model to study how the presence of a nearby dust grain affects the development of a grain's charge distribution. We demonstrate that a smaller grain–grain separation results in a reduced net charge on each grain. For grains in a flowing plasma, dipole moments are unaffected by close approach except when one grain is directly in the ‘wake’ of the other grain. The studies here show that monopole and dipole electrostatic forces are present when dust is bathed in flowing plasma. Recent infrared studies suggest that a large fraction of young stars have dusty envelopes [G. Schilling, Science286, 66 (1999)]. In the formation of accretion discs around young stars, dust–plasma interactions are probably important. Full details on the calculations of the results discussed in this paper are summarized from a more complete treatment of the subject by Manweiler [PhD Dissertation, University of Kansas (1997)].

Ion kinetic effects on the wake potential behind a dust grain in a flowing plasma

2000 ◽  
Vol 7 (6) ◽  
pp. 2320-2328 ◽  
Author(s):  
D. Winske ◽  
W. Daughton ◽  
D. S. Lemons ◽  
M. S. Murillo
Keyword(s):  
Flowing Plasma ◽  
Kinetic Effects ◽  
Dust Grain

Effect of a dipole moment on the wake potential of a dust grain in a flowing plasma

2000 ◽  
Vol 61 (6) ◽  
pp. 7246-7248 ◽  
Author(s):  
Osamu Ishihara ◽  
S. V. Vladimirov ◽  
N. F. Cramer
Keyword(s):  
Dipole Moment ◽  
Flowing Plasma ◽  
Dust Grain

scholarly journals Approximate Analytical Solution of Nonlinear Evolution Equations

2020 ◽  
Author(s):  
Laxmikanta Mandi ◽  
Kaushik Roy ◽  
Prasanta Chatterjee
Keyword(s):  
Acoustic Waves ◽  
Evolution Equations ◽  
Solitary Wave Solution ◽  
Perturbation Technique ◽  
Nonlinear Evolution Equations ◽  
Charged Dust ◽  
De Vries ◽  
Frame Work ◽  
Dust Grain ◽  
Charged Ions

Analytical solitary wave solution of the dust ion acoustic waves (DIAWs) is studied in the frame-work of Korteweg-de Vries (KdV), damped force Korteweg-de Vries (DFKdV), damped force modified Korteweg-de Vries (DFMKdV) and damped forced Zakharov-Kuznetsov (DFZK) equations in an unmagnetized collisional dusty plasma consisting of negatively charged dust grain, positively charged ions, Maxwellian distributed electrons and neutral particles. Using reductive perturbation technique (RPT), the evolution equations are obtained for DIAWs.

scholarly journals Resolved spectral variations of the centimetre-wavelength continuum from the ρ Oph W photo-dissociation-region

2021 ◽  
Author(s):  
Simon Casassus ◽  
Matías Vidal ◽  
Carla Arce-Tord ◽  
Clive Dickinson ◽  
Glenn J White ◽  
...  
Keyword(s):  
Molecular Cloud ◽  
Dust Emission ◽  
Image Synthesis ◽  
Microwave Emission ◽  
Radio Continuum ◽  
Continuum Emission ◽  
Parametric Image ◽  
Physical Conditions ◽  
Morphological Differences ◽  
Dust Grain

Abstract Cm-wavelength radio continuum emission in excess of free-free, synchrotron and Rayleigh-Jeans dust emission (excess microwave emission, EME), and often called ‘anomalous microwave emission’, is bright in molecular cloud regions exposed to UV radiation, i.e. in photo-dissociation regions (PDRs). The EME correlates with IR dust emission on degree angular scales. Resolved observations of well-studied PDRs are needed to compare the spectral variations of the cm-continuum with tracers of physical conditions and of the dust grain population. The EME is particularly bright in the regions of the ρ Ophiuchi molecular cloud (ρ Oph) that surround the earliest type star in the complex, HD 147889, where the peak signal stems from the filament known as the ρ Oph-W PDR. Here we report on ATCA observations of ρ Oph-W that resolve the width of the filament. We recover extended emission using a variant of non-parametric image synthesis performed in the sky plane. The multi-frequency 17 GHz to 39 GHz mosaics reveal spectral variations in the cm-wavelength continuum. At ∼30 arcsec resolutions, the 17-20 GHz intensities follow tightly the mid-IR, Icm∝I(8 μm), despite the breakdown of this correlation on larger scales. However, while the 33-39 GHz filament is parallel to IRAC 8 μm, it is offset by 15–20 arcsec towards the UV source. Such morphological differences in frequency reflect spectral variations, which we quantify spectroscopically as a sharp and steepening high-frequency cutoff, interpreted in terms of the spinning dust emission mechanism as a minimum grain size acutoff ∼ 6 ± 1 Å that increases deeper into the PDR.

scholarly journals The role of radiolysis in the modelling of C2H4O2 isomers and dimethyl ether in cold dark clouds

2020 ◽  
Vol 500 (3) ◽  
pp. 3414-3424
Author(s):  
Alec Paulive ◽  
Christopher N Shingledecker ◽  
Eric Herbst
Keyword(s):  
Gas Phase ◽  
Dimethyl Ether ◽  
Recent Observation ◽  
Cosmic Ray ◽  
Thermal Method ◽  
Dark Clouds ◽  
Ice Surface ◽  
Dust Grain ◽  
Complex Organic

ABSTRACT Complex organic molecules (COMs) have been detected in a variety of interstellar sources. The abundances of these COMs in warming sources can be explained by syntheses linked to increasing temperatures and densities, allowing quasi-thermal chemical reactions to occur rapidly enough to produce observable amounts of COMs, both in the gas phase, and upon dust grain ice mantles. The COMs produced on grains then become gaseous as the temperature increases sufficiently to allow their thermal desorption. The recent observation of gaseous COMs in cold sources has not been fully explained by these gas-phase and dust grain production routes. Radiolysis chemistry is a possible non-thermal method of producing COMs in cold dark clouds. This new method greatly increases the modelled abundance of selected COMs upon the ice surface and within the ice mantle due to excitation and ionization events from cosmic ray bombardment. We examine the effect of radiolysis on three C2H4O2 isomers – methyl formate (HCOOCH3), glycolaldehyde (HCOCH2OH), and acetic acid (CH3COOH) – and a chemically similar molecule, dimethyl ether (CH3OCH3), in cold dark clouds. We then compare our modelled gaseous abundances with observed abundances in TMC-1, L1689B, and B1-b.

On Robe’s restricted problem with a modified Newtonian potential

2020 ◽  
Vol 18 (01) ◽  
pp. 2150005 ◽  
Author(s):  
Elbaz I. Abouelmagd ◽  
Abdullah A. Ansari ◽  
M. H. Shehata
Keyword(s):  
Equilibrium Points ◽  
Equations Of Motion ◽  
Underwater Vehicles ◽  
Newtonian Potential ◽  
Second Primary ◽  
The Moon ◽  
Primary Body ◽  
Out Of Plane ◽  
Robe’S Restricted Problem ◽  
Dust Grain

We analyze the existence of equilibrium points for a particle or dust grain in the framework of unperturbed and perturbed Robe’s motion. This particle is moving in a spherical nebula consisting of a homogeneous incompressible fluid, which is considered as the primary body. The second primary body creates the modified Newtonian potential. The perturbed mean motion and equations of motion are found. The equilibrium points (i.e. collinear, noncollinear and out–of–plane points), along with the required conditions of their existence are also analyzed. We emphasize that this analysis can be used to study the oscillations of the Earth’s core under the attraction of the Moon and it is also applicable to study the motion of underwater vehicles.

scholarly journals Connecting the Interstellar Gas and Dust Properties in Distant Galaxies Using Quasar Absorption Systems

2015 ◽  
Vol 11 (S315) ◽  
Author(s):  
Monique C. Aller ◽  
Varsha P. Kulkarni ◽  
Donald G. York ◽  
Daniel E. Welty ◽  
Giovanni Vladilo ◽  
...  
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Absorption Feature ◽  
Dust Grains ◽  
Interstellar Gas ◽  
Chemical Enrichment ◽  
Normal Galaxies ◽  
History Of ◽  
Dust Grain ◽  
Grain Properties

AbstractGas and dust grains are fundamental components of the interstellar medium and significantly impact many of the physical processes driving galaxy evolution, such as star-formation, and the heating, cooling, and ionization of the interstellar material. Quasar absorption systems (QASs), which trace intervening galaxies along the sightlines to luminous quasars, provide a valuable tool to directly study the properties of the interstellar gas and dust in distant, normal galaxies. We have established the presence of silicate dust grains in at least some gas-rich QASs, and find that they exist at higher optical depths than expected for diffuse gas in the Milky Way. Differences in the absorption feature shapes additionally suggest variations in the silicate dust grain properties, such as in the level of grain crystallinity, from system-to-system. We present results from a study of the gas and dust properties of QASs with adequate archival IR data to probe the silicate dust grain properties. We discuss our measurements of the strengths of the 10 and 18 μm silicate dust absorption features in the QASs, and constraints on the grain properties (e.g., composition, shape, crystallinity) based on fitted silicate profile templates. We investigate correlations between silicate dust abundance, reddening, and gas metallicity, which will yield valuable insights into the history of star formation and chemical enrichment in galaxies.

Measurement of the electrical properties of a flowing plasma, including a critical comparison of probe experiment and theory

1969 ◽  
Vol 3 (2) ◽  
pp. 161-178 ◽  
Author(s):  
E. W. Billington
Keyword(s):  
Major Axis ◽  
Wire Mesh ◽  
Ion Temperature ◽  
Plasma Parameters ◽  
Direct Exposure ◽  
Current Voltage ◽  
Double Electrode ◽  
Flowing Plasma ◽  
Current Voltage Characteristics ◽  
Mesh Grid

The primary quantities characterizing the electricaJ carriers of a flowing plasma in a low density wind tunnel have been determined from measurements using electrostatic probes immersed in the plasma. With the exception of the ion temperature, the plasma parameters have been obtained from the current—voltage characteristics of two types of single electrode probe. The probes consist of a cylinder, the major axis of which is aligned parallel to the flow of the plasma, and a disk, the exposed surface of which is normal to the direction of flow. Experiments with a double electrode probe consisting of a disk-shaped collector electrode which is screened from direct exposure to the plasma by a fine wire mesh, grid electrode, made it possible to obtain current—voltage characteristics with the ion and electron components separated from one another. From the current—voltage characteristic corresponding to collection of ions, using the screen grid probe, values of the ion temperature and drift velocity have been obtained. The measurements have been made at various points along the centre line of flow, for one particular value of the flow rate using argon as the test gas. For a given position of the probes, one value of the ion temperature has been evaluated, together with two independent values of each of the other primary quantities characterizing the electrical carriers of a flowing plasma. Each pair of values agree satisfactorily amongst themselves, good agreement being generally obtained between probe theory and experiment.

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