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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：10 Percentile：60.68(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.
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：24.47(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.
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：24.69(Physics, Fluids & Plasmas)no abstracts in English
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：37.16(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.
Tomita, Yukihiro*; Smirnov, R.*; Takizuka, Tomonori; Tskhakaya, D.*
Journal of Plasma Physics, 72(6), p.1015 - 1018, 2006/12
Times Cited Count：2 Percentile：7.04(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.
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：14.62(Physics, Fluids & Plasmas)no abstracts in English
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：21.49(Physics, Fluids & Plasmas)no abstracts in English
