Quantum approach to light scattering by a charged dust grain

1979 ◽  
Vol 54 (2) ◽  
pp. 394-400 ◽  
Author(s):  
P. Chiappetta
Keyword(s):  
Light Scattering ◽  
Charged Dust ◽  
Quantum Approach ◽  
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.

Charged dust grain acceleration in tokamak edges

2008 ◽  
Vol 372 (12) ◽  
pp. 2053-2055 ◽  
Author(s):  
P.K. Shukla ◽  
N.L. Tsintsadze
Keyword(s):  
Charged Dust ◽  
Dust Grain

Retention of Small Charged Dust in Planet Forming Disks

2018 ◽  
Vol 14 (S345) ◽  
pp. 283-284
Author(s):  
Vitaly Akimkin
Keyword(s):  
Coulomb Repulsion ◽  
Central Star ◽  
Charged Dust ◽  
Micron Size ◽  
Disk Evolution ◽  
Small Grains ◽  
Fast Drift ◽  
Dust Grain ◽  
Dust Evolution ◽  
Dust Charging

AbstractDust evolution in disks around young stars is a key ingredient for the global disk evolution and accompanying planet formation. The mutual sticking of initially small grains is not straightforward and can be hampered by several processes. This includes dust grain bouncing, fragmentation, electrostatic repulsion and fast drift to the central star. In this study we aim at theoretical modeling of the dust coagulation coupled with the dust charging and disk ionization calculations. We show that the electrostatic barrier is a strong restraining factor to the coagulation of micron-size dust. While the sustained turbulence helps to overcome the electrostatic barrier, dust fluffiness limits this opportunity. Coulomb repulsion may keep a significant fraction of m dust in large regions of protoplanetary disks.

Nonlinear dynamics of a charged dust grain in a plasma

1997 ◽  
Vol 4 (12) ◽  
pp. 4210-4217 ◽  
Author(s):  
Yves Elskens ◽  
David P. Resendes ◽  
J. T. Mendonça
Keyword(s):  
Nonlinear Dynamics ◽  
Charged Dust ◽  
Dust Grain

scholarly journals Excitation of Gould–Trivelpiece mode by streaming particles in dusty plasma

2019 ◽  
Vol 37 (01) ◽  
pp. 122-127 ◽  
Author(s):  
Daljeet Kaur ◽  
Suresh C. Sharma ◽  
R.S. Pandey ◽  
Ruby Gupta
Keyword(s):  
Dusty Plasma ◽  
Collisionless Plasma ◽  
Charged Dust ◽  
Particle Interactions ◽  
First Order ◽  
Transfer Processes ◽  
Ion Plasma ◽  
Energy And Momentum ◽  
Dust Grain ◽  
First Order Perturbation

AbstractIn this paper, we study the excitation of Gould–Trivelpiece (TG) waves by streaming ions in dusty plasma and derive the dispersion relation of the excited waves using first-order perturbation theory. The motion of charged particles is controlled by electromagnetic fields in plasma. The energy transfer processes which occur in this collisionless plasma are believed to be based on wave–particle interactions. We have found that the TG waves may be generated in a streaming ion plasma via Cerenkov interaction, and the ions may be accelerated by TG waves via cyclotron interaction, which enable energy and momentum transfer. The variation in the growth rate of TG wave with dust grain size and relative density of negatively charged dust grains is also studied. The dust can cause an unstable TG mode to be stable in Doppler resonance, and can induce an instability in Cerenkov interaction.

A Monte Carlo Model for Light Scattering by Dark Nebulae

1979 ◽  
Vol 3 (5) ◽  
pp. 312-315
Author(s):  
M. I. Darby ◽  
D. J. King ◽  
K. N. R. Taylor
Keyword(s):  
Monte Carlo ◽  
Light Scattering ◽  
Surface Brightness ◽  
Transfer Problem ◽  
Dust Cloud ◽  
Monte Carlo Model ◽  
Radiative Transfer Problem ◽  
Monte Carlo Techniques ◽  
Dust Grain ◽  
Model Approach

The Thumbprint Nebula (TPN) in Chamaeleon (first described by Fitzgerald (1974), and shown in Figure 1) is a good example of the class of dense, dark nebulae that exhibit dark cores and bright rims, and have been referred to (Lynds 1967) as ‘bright dark nebulae’. Early observations of these nebulae established that the dust grains within them were strongly forward-scattering (Struve and Elvey 1936, Struve 1937). However, the treatment of the radiative transfer problem was too inadequate to permit more than tentative conclusions regarding the nebulae. In more recent years, with the advent of modern computers, the transfer of radiation through a dust cloud has been treated more rigorously, using Monte Carlo techniques (Mattila 1970, Witt and Stephens 1974). Witt and Stephens (1974) have demonstrated that for a dense nebula the surface brightness profile is sensitive to the dust grain density distribution within the cloud and to the scattering properties of the grains. The scattering model approach can be valuable in the investigation of very opaque dark nebulae that cannot be studied by conventional star counting techniques. This has been demonstrated in the case of the TPN by Fitzgerald et al (1976), who used the Witt and Stephens model.

scholarly journals Magnetic diffusivities in 3D radiative chemo-hydrodynamic simulations of protostellar collapse

2017 ◽  
Vol 603 ◽  
pp. A105 ◽  
Author(s):  
Natalia Dzyurkevich ◽  
Benoît Commerçon ◽  
Pierre Lesaffre ◽  
Dimitry Semenov
Keyword(s):  
Magnetic Fields ◽  
Hall Effect ◽  
Dynamical Evolution ◽  
Ambipolar Diffusion ◽  
Charged Dust ◽  
Chemical Abundances ◽  
Magnetic Diffusivity ◽  
Mean Size ◽  
Protostellar Collapse ◽  
Dust Grain

Context. Both theory and observations of star-forming clouds require simulations that combine the co-evolving chemistry, magneto-hydrodynamics, and radiative transfer in protostellar collapse simulation. A detailed knowledge of self-consistent chemical evolution for the main charge carriers (both gas species and dust grains) allows us to correctly estimate the rate and nature of magnetic dissipation in the collapsing core. This knowledge is critical to answer one of the most significant issues of star and planet formation: what is the magnitude and spatial distribution of magnetic flux as the initial condition to protoplanetary disk evolution? Aims. We use a chemo-dynamical version of RAMSES, which is described in a companion publication, to follow the chemo-dynamical evolution of collapsing dense cores with various dust properties and interpret differences that occur in magnetic diffusivity terms. These differences are crucial to circumstellar disk formation. Methods. We performed 3D chemo-dynamical simulations of 1 M⊙ isolated dense core collapse for a range in dust size assumptions. The number density of dust and its mean size affect the efficiency of charge capturing and the formation of ices. The radiative hydrodynamics and dynamical evolution of chemical abundances were used to reconstruct the magnetic diffusivity terms for clouds with various magnetisation. Results. The simulations are performed for a mean dust size ranging from 0.017 μm to 1 μm, and we adopt both a fixed dust size and a dust size distribution. The chemical abundances for this range of dust sizes are produced by RAMSES and serve as inputs to calculations of Ohmic, ambipolar, and Hall diffusivity terms. Ohmic resistivity only plays a role at the late stage of the collapse in the innermost region of the cloud where gas density is in excess of a few times 1013 cm-3. Ambipolar diffusion is a dominant magnetic diffusivity term in cases where mean dust size is a typical ISM value or larger. We demonstrate that the assumption of a fixed dominant ion mass can lead to a one order of magnitude mismatch in the ambipolar diffusion magnitude. The negative Hall effect is dominant during the collapse in case of small dust, i.e. for the mean dust size of 0.02 μm and smaller; we connect this effect to the dominance of negatively charged grains. We find that the Hall effect reverses its sign for mean dust size of 0.1 μm and smaller. The phenomenon of the sign reversal strongly depends on the number of negatively charged dust relative to the ions and the quality of coupling of the charged dust to the magnetic fields. We have adopted different strengths of magnetic fields, β = Pgas/Pmag = 2,5,25. We observe that the variation on the field strength only shifts the Hall effect reversal along the radius of the collapsing cloud, but does not prevent it. Conclusions. The dust grain mean size appears to be the parameter with the strongest impact on the magnitude of the magnetic diffusivity, dividing the collapsing clouds in Hall-dominated and ambipolar-dominated clouds and affecting the size of the resulting disks. We propose to link the dust properties and occurrence and size of disk structures in Class 0 young stellar objects. The proper accounting for dust grain growth in the radiative magneto-hydrodynamical collapse models are as important as coupling the dynamics of the collapse with the chemistry.

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