We study equations of a non-gauge vector field in a spherically symmetric static metric. The constant vector field with a scale arrangement of components, the temporal component about the Planck mass m Pl and the radial component about M suppressed with respect to the Planck mass, serves as a source of metric reproducing flat rotation curves in dark halos of spiral galaxies, so that the velocity of rotation v 0 is determined by the hierarchy of scales: √ 2v 2 0 = M/m Pl , and M ∼ 10 12 GeV. A natural estimate of Milgrom's acceleration about the Hubble rate is obtained. PACS numbers: 04.40.−b, 95.35.+d, 04.40.Nr, 98.62.Gq 1 An example of an alternative description due to a modification of gravity is given in [15].
The current national project on coated conductors using Y-system superconductors has been carried out over the project period (FY2003-FY2007). In this paper, the current status and the future prospect of this project are reviewed. The high performance tape development group, consisting of Fujikura and SRL-NCCC, has worked on the tape by PLD-REBCO superconducting layers on PLD-CeO 2 /IBAD-GZO buffered substrates. A high product of I c and L, higher than 112 166 A m, was achieved in a 368 m-304.8 A GdBCO tape whose I c value is mostly above 350 A/cm in width. The performance under magnetic field was also improved up to 42 A at 3 T in a GdBCO short film with doping of ZrO 2 . 61 m long GdBCO tape with ZrO 2 doping showed a high I c value of 220 A at self field and 30 A at 3 T. On the other hand, another group focusing on low production cost has worked on TFA-MOD and MOCVD processes. The extremely high I c value of 735 A/cm-w was obtained in TFA-MOD films on PLD-CeO 2 /IBAD-GZO/Hastelloy substrate due to the effect of Ba-poor nominal composition. In efforts towards long tape production by the SWCC group, a 200 m long tape with a high I c value of 200 A/cm-w was obtained using a batch-type furnace. The I c × L value of this tape was 40 000 A m, which is the highest value in the world obtained by the TFA-MOD process. Based on the above achievements in coated conductor process development, two new additional goals were set in the project. One is the development of extremely low cost tape and the other is the development of the basic technologies for making electric power devices of cables, transformers, motors, current-limiters and cryocoolers. Some of the new investigations have already revealed marvellous results, such as a 15 kW motor, low AC loss coils, low AC loss cables, etc.
The physics of sawtooth oscillations in plasmas produced by the Alcator C-Mod machine is discussed by identifying the regimes that characterize these oscillations, which occur in the central value of the electron temperature, as measured by X ray and/or ECE diagnostics. Sawteeth are generally present in ohmic as well as in RF heated plasmas. It is shown by numerical analysis that these plasmas are stable to ideal internal, pressure driven modes. Hence, the modes responsible for the crash phase of the sawteeth have to be resistive in nature. This is confirmed by numerical computations using a resistive code. The role of energetic ions, produced by ion cyclotron heating, is also discussed.
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