Home OALib Journal OALib PrePrints Submit Ranking News My Lib FAQ About Us Follow Us+
 Title Keywords Abstract Author All
Search Results: 1 - 10 of 100 matches for " "
 Page 1 /100 Display every page 5 10 20 Item
 Physics , 2006, DOI: 10.1063/1.2397042 Abstract: It is proved that irrespective of compressibility tokamak steady states with purely poloidal mass flow can not exist in the framework of either magnetohydrodynamics (MHD) or Hall MHD models. Non-existence persists within single fluid plasma models with pressure anisotropy and incompressible flows.
 Brazilian Journal of Physics , 1997, DOI: 10.1590/S0103-97331997000300009 Abstract: this paper describes the theoretical models and the method used in the design of the poloidal field coils system for the ete (experimento tokamak esférico small-aspect-ratio tokamak. the method is illustrated with the equilibrium configurations obtained for ete.
 Ludwig Gerson Otto Brazilian Journal of Physics , 1997, Abstract: This paper describes the theoretical models and the method used in the design of the poloidal field coils system for the ETE (Experimento Tokamak Esférico small-aspect-ratio tokamak. The method is illustrated with the equilibrium configurations obtained for ETE.
 Physics , 2013, Abstract: The connection between the poloidal and the toroidal rotation of plasma in tokamak is important for the high confinement regimes, in particular in reactor regime. The sudden onset of closed convection structures in the poloidal section, due to the baroclinic production of vorticity, will sustain a fast increase of the poloidal velocity and a substantial effect on the toroidal rotation. However this is limited to the short time of the onset transition. In real plasma however there is random generation and suppression of convection cells and the sequence of these transient events can prove able to sustain the effect on the toroidal rotation. We formulate a simplified model which consists of a laminar sheared, regular, flow situated at the boundary of a region of drift-wave turbulence. Vortical structures, randomly generated in this turbulent region are spontaneously advected toward the flow and are absorbed there, sustaining with their vortical content, the sheared flow. We examine this dynamics in the wavenumber $\mathbf{k}$ space, using reasonable approximations. We derive a system of equations (which is a class of Davey-Stewartson system) and find that indeed, the vortices advected and absorbed into the layer can preserve its regular, poloidal, flow.
 中国物理 B , 1998, Abstract: The destabilization of the poloidal rotation for the species of ions with the poloidally inhomogeneous sources or sinks is studied in multiple ion species tokamak plasmas. Based on the fluid equations, the evolution equation of the poloidal ion rotation speed is derived analytically. The magnitude of the inhomogeneous sources or sinks needed to destabilize the rotation is shown to be proportional to the ion density. It is suggested that the poloidal plasma rotation can be generated by destabilizing the rotation of the minority ions.
 Physics , 2013, Abstract: The structure of poloidal and toroidal flows of trace impurities in the edge pedestal of tokamak plasmas is studied analytically and numerically. Parallel momentum balance is analysed upon retaining the following terms: poloidal and toroidal centrifugal forces (inertia), pressure force, electric force, and the friction force. It is shown that, when the poloidal flow is such to produce a properly defined Mach number of order unity somewhere on the flux surface, shock fronts can form. The shock fronts can modify the predicted asymmetry structures in both the flow and the density profile along the poloidal arc. Predictions of the theory are shown against experimental observations in the ASDEX Upgrade tokamak, showing good qualitative and quantitative agreement if the inertia term associated with the poloidal flow is retained.
 Journal of Nuclear and Particle Physics , 2012, DOI: 10.5923/j.jnpp.20120204.05 Abstract: In this contribution we presented comparative measurements of tokamak plasma position. In the first technique, two poloidal flux loop were designed and installed on outer surface of the IR-T1 tokamak chamber, and then the plasma displacement obtained from them. To compare the result obtained using this method analytical solution of the Grad-Shafranov equation based on expansion of free functions as quadratic in flux function is also experimented on IR-T1. Results of the two methods are in good agreement with each other.
 中国物理 B , 2003, Abstract: The poloidal rotation velocity of neutral hydrogen atoms is measured using the Doppler shift of the Hα spectral line emitted in the CT-6B tokamak. The poloidal rotation of hydrogen atoms is generated through the collisions and charge-exchanges with main ions (protons). Therefore, the rotation direction of main ions can be deduced from that of neutral hydrogen atoms. The experimental results show that the main ions rotate in the electron diamagnetic drift direction, the same as the impurity ions, in the plasma core. The neutral hydrogen atoms rotate also in the electron diamagnetic drift direction in the edge region of the plasma. However, the rotation direction of main ions in the edge region cannot be judged from the experimental result due to the long mean free path of hydrogen atoms in the edge region. An inward diffusion flux of hydrogen atoms toward the torus inside with a velocity of the same order of magnitude as their poloidal rotation is also observed.
 Journal of Nuclear and Particle Physics , 2012, DOI: 10.5923/j.jnpp.20120202.05 Abstract: In this paper, The first results of the movable emissive limiter biasing experiments performed on the IR-T1 Tokamak are presented. For this purpose, a moveable emissive limiter system was designed, constructed, and installed on the IR-T1 Tokamak. The emissive biased limiter is positioned at r/a=1.05, and the biased voltage which is varied from -350 to 350 V applied between the head of emissive limiter and vacuum chamber. Then, the plasma current, safety factor, poloidal beta and plasma resistance in the absence and presence of the emissive biased limiter in negative polarity were measured and results were compared with the cold limiter biasing in negative polarity. Much more plasma parameters such as the magneto hydrodynamics instability and plasma energy confinement time are determined by using these parameters. Diamagnetic loops and loop voltage can be utilized in measurements of the plasma poloidal beta and plasma resistance. Result are compared and discussed.
 Brazilian Journal of Physics , 2002, DOI: 10.1590/S0103-97332002000100015 Abstract: a new regime of runaway discharges has been observed in the tcabr tokamak. one of the most distinctive features of this regime is the effect of plasma detachment from the limiter. this experimental fact can only be explained by the volume recombination, which requires a low-temperature plasma. the analysis of the energy and particle balance in the system plasma-relativistic runaway beam in tcabr, which takes into account only the collisional mechanism of the heat transfer from runaways to thermal electrons, predicts electron temperatures te = 0.1 - 2 ev; the temperature decreases with the neutral density increase. the recombination process with the rate constant around 10-16 m3/s is required for the explanation of plasma density behavior in the experiment. at present, it is difficult to conclude about the mechanism of recombination. more reliable and detailed experimental data, mainly about the plasma temperature, are necessary.
 Page 1 /100 Display every page 5 10 20 Item