Nonradiating current configurations attract attention of physicists for many years as possible models of stable atoms. One intriguing example of such a nonradiating source is known as 'anapole'. An anapole mode can be viewed as a composition of electric and toroidal dipole moments, resulting in destructive interference of the radiation fields due to similarity of their far-field scattering patt...

The results of hybrid MHD-particle simulations of the Alfvén mode dynamics in a reversed-shear beam-heated DIII-D discharge are reported and compared with the experimental observations. Specific attention is devoted to the inclusion, in the numerical model, of nonlinear coupling between different toroidal mode numbers.

It is shown that neoclassical theory explains quite well the origin of the co-current toroidal rotation velocity measured in the core of stationary Alcator C-Mod edge localized mode (ELM)-free Ohmic high confinement (H)-mode discharges. Both edge and core toroidal rotation velocity profiles are determined to a good approximation by the edge ion temperature and density pedestals, where the gradi...

Impurity toroidal rotation has been observed in the centre of Alcator C-Mod ion cyclotron range of frequencies (ICRF) heated plasmas, from the Doppler shifts of argon X ray lines. Rotation velocities greater than 1.2×10 cm/s (ω = 200 krad/s) in the co-current direction have been observed in H mode discharges that had no direct momentum input. There is a correlation between the increase in the c...

Experiments designed to characterize both stable and unstable Alfvén eigenmodes are a key part of the Alcator C-Mod physics program. Stable intermediate toroidal mode number (3 ≤ n ≤ 14) Alfvén eigenmodes, which are expected to be the most unstable in ITER, are excited with a set of active MHD antennas and their damping rates are measured as a function of plasma parameters. This is part of an i...

GTC gyrokinetic particle simulations of DIII-D discharge #142111 near 525ms find a radial localization of toroidal Alfven eigenmode (TAE) due to the modification of the MHD mode structure, i.e., nonperturbative contribution by energetic particles (EP). The EP-driven TAE has a radial mode width much smaller than that predicted by the MHD theory. The TAE radial position peaks at and moves with th...

Results of three-dimensional (3D) numerical simulations of field-reversed configurations (FRCs) are presented. The emphasis of this work is on the nonlinear evolution of magnetohydrodynamic (MHD) instabilities in kinetic FRCs and the new FRC formation method by counter-helicity spheromak merging. Kinetic simulations show nonlinear saturation of the n = 1 tilt mode, where n is the toroidal mode ...

Observations of long-term north-south asymmetry in solar activity demand the equator-symmetric (quadrupolar) mode be present magnetic field line with dominant antisymmetric (dipolar) mode. This paper proposes treating sunspot area as a proxy for subsurface toroidal flux to infer quadrupolar dynamo from data. Toroidal pseudo-fluxes (PF) northern and southern hemispheres are defined signed plus o...

Small 3D magnetic perturbations have many interesting and useful effects on tokamak and quasi-symmetric stellarator plasmas. Plasma transport equations that include these effects, most notably on diamagnetic-level toroidal plasma rotation, have recently been developed. The 3D magnetic perturbations and their plasma effects can be classified according to their toroidal mode number n. Low n non-r...

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