Gyrokinetic δf particle simulation is used to investigate the nonlinear saturation mechanisms in collisionless trapped electron mode (CTEM) turbulence. It is found that the importance of zonal flow is parameter sensitive and is well characterized by the shearing rate formula. The effect of zonal flow is empirically found to be sensitive to temperature ratio, magnetic shear and electron temperat...

The external fields of optical whispering gallery modes may be used to confine atoms in stable orbits around a dielectric microsphere. As an example, a toroidal dipole-force trap (atom gallery) for three-level atoms is investigated, and the possibility of achieving an atomic (matter-wave) resonator is discussed. The extremely small electromagnetic mode volumes and high Q's of the whispering gal...

The toroidal rotation of H-mode plasmas in ASDEX Upgrade is studied in the outermost 5 cm of the confined plasma. The projection of the rotation velocity along the line of sight (approximately toroidal) is measured using charge exchange recombination spectroscopy, with a radial resolution of up to 3 mm and a temporal resolution of 1.9 ms. At about 1 cm inside the separatrix the rotation exhibit...

We present numerical models of hydromagnetic instabilities under the conditions prevailing in a stably stratified, non-convective stellar interior, and compare them with previous results of analytic work on instabilities in purely toroidal fields. We confirm that an m = 1 mode (‘kink’) is the dominant instability in a toroidal field in which the field strength is proportional to distance from t...

Several tokamak experiments have reported the existence of plasma equilibria with a zero total toroidal current in their AC operations. By taking a plasma profile model based on linear functions of the poloidal flux function ψ , a variety of equilibrium configurations with a zero total toroidal current have been found. The MHD_N0 stability code [1] is able to compute axisymmetric mode stability...

Global gyrokinetic particle simulation of collisionless trapped electron mode turbulence in toroidal plasmas finds both diffusive and convective electron motion using a Lagrangian analysis. The convective motion is identified using simulation and analytic theory to arise from the conservation of the second invariant when resonant trapped electrons lose kinetic energy to the drift wave. A resona...

In this paper, we present a time-domain analysis of a short pulse partial-waveguide FEL oscillator employing toroidal mirrors and a hole outcoupling. The use of toroidal mirrors with optimized radius of curvatures helps to reduce cavity losses arising from the mismatch of the free space propagating optical field into a waveguided one. We introduce semi-analytical expressions for the calculation...

A series of novel toroidal cyclo-2,9-tris-1,10-phenanthroline macrocycles with an unusual hexaaza cavity are reported. Nickel-mediated Yamamoto aryl-aryl coupling was found to be a versatile tool for the cyclotrimerization of functionalized 1,10-phenathroline precursors. Due to the now improved processability, both liquid-crystalline behavior in the bulk phase and two-dimensional self-assembly ...