Simulation of transition dynamics to high confinement in fusion plasmas

The transition dynamics from the low (L) to the high (H) confinement mode in magnetically confined plasmas is investigated using a first-principles four-field fluid model. Numerical results are in close agreement with measurements from the Experimental Advanced Superconducting Tokamak - EAST. Particularly, the slow transition with an intermediate dithering phase is well reproduced by the numerical solutions. Additionally, the model reproduces the experimentally determined L-H transition power threshold scaling that the ion power threshold increases with increasing particle density. The results hold promise for developing predictive models of the transition, essential for understanding and optimizing future fusion power reactors

Uneven batch data alignment with application to the control of batch end-product quality

keywords: Variable batch lengths keywords: Variable batch lengths keywords: Variable batch lengths keywords: Variable batch lengths keywords: Variable batch length

Global Cosmological Parameters Determined Using Classical Double Radio Galaxies

A sample of 20 powerful extended radio galaxies with redshifts between zero and two were used to determine constraints on global cosmological parameters. Data for six radio sources were obtained from the VLA archive, analyzed, and combined with the sample of 14 radio galaxies used previously by Guerra & Daly to determine cosmological parameters. The results are consistent with our previous results, and indicate that the current value of the mean mass density of the universe is significantly less than the critical value. A universe with $\Omega_m$ of unity is ruled out at 99.0% confidence, and the best fitting values of $\Omega_m$ in matter are $0.10^{+0.25}_{-0.10}$ and $-0.25^{+0.35}_{-0.25}$ assuming zero space curvature and zero cosmological constant, respectively. Note that identical results obtain when the low redshift bin, which includes Cygnus A, is excluded; these results are independent of whether the radio source Cygnus A is included. The method does not rely on a zero-redshift normalization. The radio properties of each source are also used to determine the density of the gas in the vicinity of the source, and the beam power of the source. The six new radio sources have physical characteristics similar to those found for the original 14 sources. The density of the gas around these radio sources is typical of gas in present day clusters of galaxies. The beam powers are typically about $10^{45} \hbox{erg s}^{-1}$.Comment: 39 pages includes 21 figures, accepted to Ap

Heat current and spin current through a carbon-nanotube-based molecular quantum pump

We investigate the heat current and spin current through a carbon-nanotube-based molecular quantum pump. We have derived a general expression for the heat current at finite frequency so that the heat current can be calculated order by order in pumping amplitudes. We have applied our theory to a carbon-nanotube-based quantum pump. The heat current generated during the parametric pumping has been calculated at small frequencies for finite pumping amplitude. At finite frequencies, we have calculated the heat current to the second order in pumping amplitudes. The photon assisted process is clearly observed in the heat current. In the presence of magnetic field, the carbon-nanotube-based quantum pump can function as a spin pump, a molecular device by which a dc pure spin current without accompanying charge current is generated at zero bias voltage via a cyclic deformation of two device parameters. The pure spin current is achieved when the Fermi energy is near the resonant level of the quantum pump. We find that the pure spin current is sensitive to system parameters such as pumping amplitude, external magnetic field, and gate voltage.published_or_final_versio