Refine your search:     
Report No.
 - 
Search Results: Records 1-13 displayed on this page of 13
  • 1

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Simulation of dynamics of carbon dust particles in the JT-60U tokamak

Tanaka, Yasunori*; Smirnov, R. D.*; Pigarov, A. Y.*; Takenaga, Hidenobu; Asakura, Nobuyuki; Uesugi, Yoshihiko*; Ono, Noriyasu*

Journal of Nuclear Materials, 415(Suppl.1), p.S1106 - S1110, 2011/08

 Times Cited Count:8 Percentile:56.22(Materials Science, Multidisciplinary)

Dust can be an important contributor to impurity contamination of the core and scrape-off-layer (SOL) plasmas in tokamak fusion devices. This is the first report about investigation of transport of carbon dust particles in case of JT-60U tokamak using the dust transport code (DUSTT). The DUSTT code takes into account various plasma-dust interaction processes. In the present report, background plasma parameters in JT-60U such as densities and temperatures of electron, ion and neutral atom were computed with the UEDGE code. Three dimensional trajectories, temperature evolution, and radius variation of dust particles launched from different positions at the inner divertor, the outer divertor and the dome structure in JT-60U tokamak were simulated numerically to study dynamics and transport of dust particles there. As a result, the lifetime of dust particles is dependent mainly on the ion density in trajectories in final term.

Journal Articles

Release conditions of dust particle from plasma-facing wall in oblique magnetic field

Tomita, Yukihiro*; Kawamura, Gakushi*; Smirnov, R.*; Takizuka, Tomonori; Tskhakaya, D.*

Journal of Nuclear Materials, 390-391, p.164 - 167, 2009/06

 Times Cited Count:3 Percentile:25.41(Materials Science, Multidisciplinary)

Release conditions of a spherical dust particle from a plasma-facing vertical wall immersed in an oblique magnetic field are studied analytically. The Poisson's equation is solved in the sheath to obtain the electric field at the wall, which repels the dust particle from the wall. The electric field decreases as the direction of the magnetic field approaches parallel to the wall. On the other hand the ion flow velocity becomes larger at moderate oblique angle than that without magnetic field. It is clarified that in the case of the strong magnetic field the critical dust radius for the release of the dust increases as magnetic field becomes more acute. In the case of the weak magnetic field, the critical radius disappears at the moderate angles of the oblique magnetic field.

Journal Articles

Effect of oblieque magnetic field on release conditions of dust particle from plasma-facing wall

Tomita, Yukihiro*; Smirnov, R. D.*; Takizuka, Tomonori; Tskhakaya, D.*

Contributions to Plasma Physics, 48(1-3), p.285 - 289, 2008/03

 Times Cited Count:6 Percentile:25.84(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Effect of truncation of electron velocity distribution on release of dust particle from plasma-facing wall

Tomita, Yukihiro*; Smirnov, R.*; Nakamura, Hiroaki*; Zhu, S.*; Takizuka, Tomonori; Tskhakaya, D.*

Journal of Nuclear Materials, 363-365, p.264 - 269, 2007/06

 Times Cited Count:5 Percentile:38.47(Materials Science, Multidisciplinary)

In the study of dust behavior in plasma it is usually assumed that plasma particles are Maxwell distributed. If the dust is located on the conducting wall, the surrounding particle distribution can significantly differ from the Maxwellian. In this work we study the effect of truncation of electron velocity distribution on release conditions of a spherical dust particle from a plasma-facing wall. The truncation effect enlarges the electric field at the wall compared compared to the Maxwellian. The stronger electric field at the wall makes the released region smaller when the gravitational force is directed from the wall.

Journal Articles

Benchmarking of lower hybrid current drive codes with application to ITER-relevant regimes

Bonoli, P. T.*; Harvey, R. W.*; Kessel, C. E.*; Imbeaux, F.*; Oikawa, Toshihiro; Schneider, M.*; Barbato, E.*; Decker, J.*; Giruzzi, G.*; Forest, C. B.*; et al.

Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03

no abstracts in English

Journal Articles

Charging of a spherical dust particle on a plasma-facing wall

Tomita, Yukihiro*; Smirnov, R.*; Takizuka, Tomonori; Tskhakaya, D.*

Journal of Plasma Physics, 72(6), p.1015 - 1018, 2006/12

 Times Cited Count:2 Percentile:7.39(Physics, Fluids & Plasmas)

The induced charge of a spherical conducting dust particle on a plasma-facing wall is studied analytically. An external non-uniform electric field is approximated by the polynomial of the axial coordinate and the bipolar coordinate is introduced in order to employ the boundary condition. The result is applied to the dust in the non-uniform electric field in the Debye sheath in front of the conducting wall. The results are useful for analyzing the shielding effects of the plasma surrounding a dust particle.

Journal Articles

Gravitational effect on release conditions of dust particle from plasma-facing wall

Tomita, Yukihiro*; Smirnov, R.*; Takizuka, Tomonori; Tskhakaya, D.*

Contributions to Plasma Physics, 46(7-9), p.617 - 622, 2006/09

 Times Cited Count:4 Percentile:15.32(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Two-dimensional simulation study on charging of dust particle on plasma-facing wall

Smirnov, R.*; Tomita, Yukihiro*; Tskhakaya, D.*; Takizuka, Tomonori

Contributions to Plasma Physics, 46(7-9), p.623 - 627, 2006/09

 Times Cited Count:6 Percentile:22.35(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Reduction of sheath potential and particle flux at a target plate by negatively charged dust particles

Tomita, Yukihiro*; Smirnov, R.*; Chutov, Y.*; Takayama, Arimichi*; Takizuka, Tomonori

Contributions to Plasma Physics, 44(1-3), p.162 - 167, 2004/04

 Times Cited Count:2 Percentile:6.67(Physics, Fluids & Plasmas)

Electrostatic potential formation due to negatively charged dust particles near a divertor plate is studied by one-dimensional kinetic analysis. It is shown that the negatively charged dust particles reduce the ion-sheath potential drop in front of the plate. Dust particles with a large radius (100 micron) reduce the potential drop significantly despite the low dust-to-plasma density ratio ($$sim$$10to-8). The plasma particle flux is reduced appreciably by the absorption by the dust particles.

Journal Articles

Particle simulation study of dust particle dynamics in sheaths

Smirnov, R.*; Tomita, Yukihiro*; Takizuka, Tomonori; Takayama, Arimichi*; Chutov, Y.*

Contributions to Plasma Physics, 44(1-3), p.150 - 156, 2004/04

 Times Cited Count:10 Percentile:33.22(Physics, Fluids & Plasmas)

Dynamics of dust particles in a divertor plasma is simulated using numerical solutions of dust momentum and charging equations in an electrostatic sheath and an ionizing presheath. Spatial distribution of plasma parameters in a divertor are obtained with particle simulations including ionization by electron-impact. We found that dust particles with a larger radius are incapable to come off a divertor plate. Middle-size dust particles come off the plate but come back to the plate. Smaller dust particles come off the plate and reach an equilibrium position in the divertor plasma.

Journal Articles

Reduction of sheath potential and dust ion-acoustic wave by negatively charged dust particles

Tomita, Yukihiro*; Smirnov, R.*; Chutov, Y.*; Takayama, Arimichi*; Takizuka, Tomonori

Purazuma, Kaku Yugo Gakkai-Shi, 6, p.429 - 432, 2004/00

Formation of an electrostatic potential due to negatively charged dust particles near a target plate was studied by one-dimensional kinetic analysis. Immovable dust particles are distributed uniformly inside a system. It is clarified that the negatively charged dust particles reduce the ion-sheath drop. A threshold dust density makes the electric field at the target plate zero. The stationary oscillation appears in the electrostatic potential for the dust density above the threshold. We confirm that this oscillation is the Dust Ion-Acoustic Wave with a wave length of the order of Debye length, where dust charges are effective to determine the coefficient.

Journal Articles

Dynamics of dust particles coming off a wall in sheath and presheath

Smirnov, R.*; Tomita, Yukihiro*; Takizuka, Tomonori; Takayama, Arimichi*; Chutov, Y.*

Purazuma, Kaku Yugo Gakkai-Shi, 6, p.752 - 755, 2004/00

Dynamics of a single dust particle in near-wall plasma is studied in wide range of dust radii and masses. Dust motion and charging equations are solved in the plasma simulated for sheath and ionizing presheath using one-dimensional particle model. It was found that balance of electric and ion drag forces acting on the dust particle provides two critical dust radii differentiating motion of dust started at the wall between pinned against the wall, short and long-range oscillating. Delayed charging causes the mass dependence of the second critical radius until transition from short to long-range oscillations becomes undistinguishable.

Journal Articles

Particle simulation study of dust particle dynamics in sheaths

Smirnov, R.*; Tomita, Yukihiro*; Takizuka, Tomonori; Takayama, Arimichi*; Chutov, Y.*

NIFS-784, 9 Pages, 2003/10

Dynamics of dust particles in a divertor plasma is simulated using numerical solutions of dust momentum and charging equations. Spatial distributions of plasma parameters in a divertor are obtained with particle simulations including electron-impact ionization. We find that the large-radius dust particles are not released from the divertor plate. The middle-size-radius particles are released but retuned to the plate. The small-radius particles can be released from the plate.

13 (Records 1-13 displayed on this page)
  • 1