Modeling of small tungsten dust grains in EAST tokamak with NDS-BOUT++

2021 ◽  
Vol 28 (12) ◽  
pp. 122503
Author(s):  
Zhuang Liu ◽  
Rui Ding ◽  
Xueqiao Xu ◽  
Nami Li ◽  
Guozhong Deng ◽  
...  
Keyword(s):  
Dust Grains

Transport of Dust Grains in Turbulent Molecular Clouds

1998 ◽  
Vol 498 (2) ◽  
pp. 757-762 ◽  
Author(s):  
B. R. Ragot
Keyword(s):  
Molecular Clouds ◽  
Dust Grains

scholarly journals Experimental Results on Scattering by Irregular and Meteoritic Dust Particles Related to Photopolarimetry of Zodiacal Light and Comets

1985 ◽  
Vol 85 ◽  
pp. 223-226
Author(s):  
K. Weiss-Wrana ◽  
R.H. Giese ◽  
R.H. Zerull
Keyword(s):  
Light Scattering ◽  
Size Range ◽  
Experimental Results ◽  
Dust Particles ◽  
Dust Grains ◽  
Scattering Function ◽  
Negative Polarization ◽  
Zodiacal Light ◽  
Cometary Dust ◽  
Characteristic Features

AbstractThe investigations of light scattering by larger meteoritic and terrestrial single grains (size range 20 μm to 120 μm ) demonstrate that the scattering properties of irregularly shaped dark opaque particles with very rough surfaces resemble the characteristic features of the empirical scattering function as derived from measurements of the zodiacal light. Purely transparent or translucent irregularly shaped particles show a quite different scattering behaviour. Furthermore irregular and multicomponent fluffy particles in the size range of a few microns were modelled by microwave analog measurements in order to explain positive and negative polarization of the light scattered by cometary dust grains.

Ultrathin Amorphous Coatings on Lunar Dust Grains

Science ◽  
1972 ◽  
Vol 175 (4023) ◽  
pp. 753-755 ◽  
Author(s):  
J. P. Bibring ◽  
J. P. Duraud ◽  
L. Durrieu ◽  
C. Jouret ◽  
M. Maurette ◽  
...  
Keyword(s):  
Dust Grains ◽  
Lunar Dust ◽  
Amorphous Coatings

scholarly journals MRI-active inner regions of protoplanetary discs. I. A detailed model of disc structure

2021 ◽  
Vol 504 (1) ◽  
pp. 280-299
Author(s):  
Marija R Jankovic ◽  
James E Owen ◽  
Subhanjoy Mohanty ◽  
Jonathan C Tan
Keyword(s):  
Energy Transport ◽  
Threshold Temperature ◽  
Mass Star ◽  
Dust Grains ◽  
Solar Mass ◽  
Detailed Model ◽  
Short Period ◽  
Pressure Maximum ◽  
Ion Emission ◽  
Protoplanetary Discs

ABSTRACT Short-period super-Earth-sized planets are common. Explaining how they form near their present orbits requires understanding the structure of the inner regions of protoplanetary discs. Previous studies have argued that the hot inner protoplanetary disc is unstable to the magnetorotational instability (MRI) due to thermal ionization of potassium, and that a local gas pressure maximum forms at the outer edge of this MRI-active zone. Here we present a steady-state model for inner discs accreting viscously, primarily due to the MRI. The structure and MRI-viscosity of the inner disc are fully coupled in our model; moreover, we account for many processes omitted in previous such models, including disc heating by both accretion and stellar irradiation, vertical energy transport, realistic dust opacities, dust effects on disc ionization, and non-thermal sources of ionization. For a disc around a solar-mass star with a standard gas accretion rate ($\dot{M}\, \sim \, 10^{-8}$ M⊙ yr−1) and small dust grains, we find that the inner disc is optically thick, and the accretion heat is primarily released near the mid-plane. As a result, both the disc mid-plane temperature and the location of the pressure maximum are only marginally affected by stellar irradiation, and the inner disc is also convectively unstable. As previously suggested, the inner disc is primarily ionized through thermionic and potassium ion emission from dust grains, which, at high temperatures, counteract adsorption of free charges on to grains. Our results show that the location of the pressure maximum is determined by the threshold temperature above which thermionic and ion emission become efficient.

scholarly journals Aperture synthesis CS and 98 GHz continuum observations of protostellar IRAS sources in Taurus

1991 ◽  
Vol 147 ◽  
pp. 353-356
Author(s):  
N. Ohashi ◽  
R. Kawabe ◽  
M. Hayashi ◽  
M. Ishiguro
Keyword(s):  
Molecular Cloud ◽  
Total Mass ◽  
T Tauri Stars ◽  
Continuum Emission ◽  
Beam Size ◽  
Dust Grains ◽  
Dynamical Mass ◽  
T Tauri ◽  
Cloud Cores ◽  
The Continuum

The CS (J = 2 — 1) line and 98 GHz continuum emission have been observed for 11 protostellar IRAS sources in the Taurus molecular cloud with resolutions of 2.6″−8.8″ (360 AU—1200 AU) using the Nobeyama Millimeter Array (NMA). The CS emission is detected only toward embedded sources, while the continuum emission from dust grains is detected only toward visible T Tauri stars except for one embedded source, L1551-IRS5. This suggests that the dust grains around the embedded sources do not centrally concentrate enough to be detected with our sensitivity (∼4 m Jy r.m.s), while dust grains in disks around the T Tauri stars have enough total mass to be detected with the NMA. The molecular cloud cores around the embedded sources are moderately extended and dense enough to be detected in CS, while gas disks around the T Tauri are not detected because the radius of such gas disks may be smaller than 70 (50 K/Tex) AU. These results imply that the total amount of matter within the NMA beam size must increase when the central objects evolve into T Tauri stars from embedded sources, suggesting that the compact and highly dense disks around T Tauri stars are formed by the dynamical mass accretion during the embedded protostar phase.

Effect of dust grains size distribution on the Bohm sheath criterion in plasmas

2020 ◽  
Vol 27 (9) ◽  
pp. 093701
Author(s):  
N. Rebiai ◽  
A. Tahraoui ◽  
Z. Kechidi
Keyword(s):  
Size Distribution ◽  
Dust Grains

Contribution of the Dust Grains to the Damping of the Electromagnetic Waves Propagating in Plasma

2013 ◽  
Vol 41 (8) ◽  
pp. 2434-2437 ◽  
Author(s):  
Ji-Zheng Duan ◽  
Juan-Fang Han ◽  
Cang-Long Wang ◽  
Yan-Xia Xu ◽  
Jian-Rong Zhang ◽  
...  
Keyword(s):  
Electromagnetic Waves ◽  
Dust Grains

scholarly journals Observations of the Leonids in Central Asia

1998 ◽  
Vol 11 (2) ◽  
pp. 1022-1022
Author(s):  
P.B. Babadzhanov
Keyword(s):  
Central Asia ◽  
Density Range ◽  
Dust Grains ◽  
Earth’S Atmosphere ◽  
Earth's Atmosphere

Observations in Central Asia in 1965-1966 by both photographic and radar methods allowed a determination of the radiants and orbits of Leonids (Babadzhanov and Getman 1970). Photographs showed that meteoroids undergo quasi-continuous fragmentation (QCF) in the Earth’s atmosphere. Taking account of QCF, the density of the Leonid meteoroids were found to lie between 1 and Agcm-3 the average being 2gcm-3 (Babadzhanov 1994), in agreement with the density range of between 0.2 and 6gcm-3 given by Maas et al (1990) for dust grains from comet P/1 Halley, with values below 0.6 being rare. Further, the icy grains have a density of about 1gcm-3 while silicate grains have a mean density 2.5 times higher.

Sign in / Sign up

Export Citation Format

Share Document