Most efficient adaptive mesh methods employ only a few strategies, including local mesh refinement (h-adaptation), movement of mesh nodes (r-adaptation), and node reconnection (c-adaptation). Despite of its simplicity, node reconnection is the least popular of the three. However, using only node reconnection the discretization error can be significantly reduced. In this paper, we develop and nu...

[1] The local three-dimensional structure of magnetic reconnection has been measured for the first time in a magnetohydrodynamic (MHD) laboratory plasma at the Swarthmore Spheromak Experiment. An array of 600 magnetic probes which resolve ion inertial length and MHD time scale dynamics on a single shot basis measured the magnetic structure of partial spheromak merging events. Counter-helicity s...

Ion diamagnetic effects on collisionless magnetic reconnection are investigated by means of numerical simulations of a Hamiltonian gyrofluid model. The work is focused in particular on the effects of inhomogeneous density equilibria in the large ∆′ regime. The linear growth rates predicted by asymptotic theory are recovered. Nonlinearly the island shape is strongly modified and the flow changes...

The two theories for magnetic reconnection, one of Sweet and Parker, and the other of Petschek, are reconciled by exhibiting an extra condition in that of Petschek which reduces his theory to that of Sweet and Parker, provided that the resistivity is constant in space. On the other hand, if the resistivity is enhanced by instabilities, then the reconnection rate of both theories is increased su...

[1] In situ observation of the Earth’s magnetosphere has identified Hall magnetic fields as a key signature of collisionless magnetic reconnection. The inflow portion of the reconnection diffusion region is further characterized by strong electron pressure anisotropy. These two features are tightly linked in a quantitative model, which is verified using fully kinetic simulations. The model pred...

145 spatial and temporal characteristics of magnetic reconnection will fuel the sometimes heated debate over what the phenomenon is like and what it can do. With the launch of NASA’s STEREO mission, expected later this year, larger baselines will become available, and there is hope that the study of solar-wind reconnection can be extended to much larger scales. At the smallest scales, NASA’s Ma...

Magnetic reconnection changes the topology of magnetic field lines to a lower-energy state. This process can liberate stored magnetic field energy and accelerate particles during unsteady, explosive events. This is one of the most important processes in astrophysical, space and laboratory plasmas. The abrupt onset and cessation has been a long-standing puzzle. We show the first three-dimensiona...

We present the results of numerical simulations of wave-induced magnetic reconnection in a model of the solar atmosphere. In the magnetic field geometry we study in this article, the waves, driven by a monochromatic piston and a driver taken from Hinode observations, induce periodic reconnection of the magnetic field, and this reconnection appears to help drive long-period chromospheric jets. B...

We present particle-in-cell simulations of collisionless magnetic reconnection in a system (like the magnetopause) with a large density asymmetry across the current layer. In the presence of an ambient component of the magnetic field perpendicular to the reconnection plane the gradient creates a diamagnetic drift that advects the X-line with the electron diamagnetic velocity. When the relative ...

Magnetic reconnection is the crucial process in the release of magnetic energy previously stored in the magnetotail in association with substorms. However, energy transfer and dissipation in the vicinity of the reconnection site is only a minor part of the energy conversion. We discuss the energy release, transport, and conversion based on largescale resistive MHD simulations of magnetotail dyn...