A. N. Simakov

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In this Letter, we put forth (and validate numerically) a fluid-based analytical theory, which predicts that fast reconnection in nonrelativistic, low-beta pair plasmas is possible in collisionless regimes. This novel theoretical result complements recent kinetic computational evidence and challenges the accepted understanding, which considers fast(More)
The study and prediction of velocities in the pedestal region of Alcator CMod are important for understanding plasma confinement and transport. In this study we examine the simplified neoclassical predictions for impurity flows using equations developed for plasmas with background ions in the Pfirsch-Schlüter (high collisionality) and banana (low(More)
We formulate a rigorous nonlinear analytical model that describes the dynamics of the diffusion (reconnection) region in driven systems in the context of electron magnetohydrodynamics (EMHD). A steady-state analysis yields allowed geometric configurations and associated reconnection rates. In addition to the well-known open X-point geometry, elongated(More)
The equilibrium plasma rotation in a general toroidal magnetic field is nearly always subsonic and is determined by the requirement that the collisional particle transport should be ambipolar in lowest order in the small-ion-gyroradius expansion. Gyrokinetic turbulence can only appreciably modify the rotation on radial length scales of order the ion(More)
Recent interest in the experimental study of tokamak plasma flow for different magnetic field geometries calls for theoretical understanding of the effects of tokamak magnetic topology changes on the flow. The consequences of total magnetic field reversal and/or X-point reversal on divergence-free plasma flow within magnetic flux surfaces is considered and(More)
A plasma confined in a dipole field exhibits unique equilibrium and stability properties. In particular, equilibria exist at all β values and these equilibria are found to be stable to ballooning modes when they are interchange stable. When a kinetic treatment is performed at low beta we also find a drift temperature gradient mode which couples to the MHD(More)
The stability of axisymmetric plasmas confined by closed poloidal magnetic field lines is considered. The results are relevant to plasmas in the dipolar fields of stars and planets, as well as the Levitated Dipole Experiment, multipoles, Z pinches and field reversed configurations. The ideal MHD energy principle is employed to study the stability of(More)
Dissipation-independent, or "fast", magnetic reconnection has been observed computationally in Hall magnetohydrodynamics (MHD) and predicted analytically in electron MHD. However, a quantitative analytical theory of reconnection valid for arbitrary ion inertial lengths, d{i}, has been lacking and is proposed here for the first time. The theory describes a(More)