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

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)].

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

Intrinsic kinetic effects during martensitic transformations

2003 ◽  
Vol 112 ◽  
pp. 133-137 ◽  
Author(s):  
A. Fraile-Rodriguez ◽  
P. P. Rodriguez ◽  
R. B. Pérez-Saez ◽  
A. Lopez-Echarri ◽  
J. San Juan
Keyword(s):  
Martensitic Transformations ◽  
Kinetic Effects ◽  
Intrinsic Kinetic

The Kinetic Effects, Caused by Thickness Fluctuations of Quantum Semiconductor Wire

2017 ◽  
Vol 9 (2) ◽  
pp. 02024-1-02024-4
Author(s):  
M. A. Ruvinskii ◽  
◽  
B. M. Ruvinskii ◽  
O. B. Kostyuk ◽  
◽  
...  
Keyword(s):  
Quantum Semiconductor ◽  
Kinetic Effects

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.

Unraveling Kinetic Effects during Photoelectrochemical Mineralization of Phenols. Rutile:Anatase TiO2 Nanotube Photoanodes under Thin-Layer Conditions

2020 ◽  
Author(s):  
Dalia Leon ◽  
Alberto Maimone ◽  
David Carvajal ◽  
Lorean Madriz ◽  
Benjamín R. Scharifker ◽  
...  
Keyword(s):  
Thin Layer ◽  
Tio2 Nanotube ◽  
Kinetic Effects

scholarly journals Modelling of Microstructure Evolution during Laser Processing of Intermetallic Containing Ni-Al Alloys

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1051
Author(s):  
Mohammad Amin Jabbareh ◽  
Hamid Assadi
Keyword(s):  
Additive Manufacturing ◽  
Rapid Solidification ◽  
Microstructure Evolution ◽  
Phase Field ◽  
Laser Processing ◽  
Field Model ◽  
Phase Field Model ◽  
Intermetallic Phases ◽  
Al Alloy ◽  
Kinetic Effects

There is a growing interest in laser melting processes, e.g., for metal additive manufacturing. Modelling and numerical simulation can help to understand and control microstructure evolution in these processes. However, standard methods of microstructure simulation are generally not suited to model the kinetic effects associated with rapid solidification in laser processing, especially for material systems that contain intermetallic phases. In this paper, we present and employ a tailored phase-field model to demonstrate unique features of microstructure evolution in such systems. Initially, the problem of anomalous partitioning during rapid solidification of intermetallics is revisited using the tailored phase-field model, and the model predictions are assessed against the existing experimental data for the B2 phase in the Ni-Al binary system. The model is subsequently combined with a Potts model of grain growth to simulate laser processing of polycrystalline alloys containing intermetallic phases. Examples of simulations are presented for laser processing of a nickel-rich Ni-Al alloy, to demonstrate the application of the method in studying the effect of processing conditions on various microstructural features, such as distribution of intermetallic phases in the melt pool and the heat-affected zone. The computational framework used in this study is envisaged to provide additional insight into the evolution of microstructure in laser processing of industrially relevant materials, e.g., in laser welding or additive manufacturing of Ni-based superalloys.

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.

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