A FLUX ROPE NETWORK AND PARTICLE ACCELERATION IN THREEDIMENSIONAL RELATIVISTIC MAGNETIC RECONNECTION
Abstract
We investigate magnetic reconnection and particle acceleration in relativistic pair plasmas with threedimensional particleincell simulations of a kineticscale current sheet in a periodic geometry. We include a guide field that introduces an inclination between the reconnecting field lines and explore outsideofthecurrent sheet magnetizations that are significantly below those considered by other authors carrying out similar calculations. Thus, our simulations probe the transitional regime in which the magnetic and plasma pressures are of the same order of magnitude. The tearing instability is the dominant mode in the current sheet for all guide field strengths, while the linear kink mode is less important even without the guide field, except in the lower magnetization case. Oblique modes seem to be suppressed entirely. In its nonlinear evolution, the reconnection layer develops a network of interconnected and interacting magnetic flux ropes. As smaller flux ropes merge into larger ones, the reconnection layer evolves toward a threedimensional, disordered state in which the resulting flux rope segments contain magnetic substructure on plasma skin depth scales. Embedded in the flux ropes, we detect spatially and temporally intermittent sites of dissipation reflected in peaks in the parallel electric field. Magnetic dissipation and particle acceleration persist until the end ofmore »
 Authors:
 Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States)
 Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)
 Publication Date:
 OSTI Identifier:
 22133961
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Astrophysical Journal; Journal Volume: 774; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; CURRENT DENSITY; ELECTRIC FIELDS; ELECTRON BEAMS; ENERGY CONVERSION; ENERGY SPECTRA; INCLINATION; LAYERS; MAGNETIC FLUX; MAGNETIC RECONNECTION; MAGNETIZATION; PARTICLES; PLASMA PRESSURE; PROTON BEAMS; RELATIVISTIC RANGE; SIMULATION; SKIN EFFECT; TEARING INSTABILITY; THREEDIMENSIONAL CALCULATIONS
Citation Formats
Kagan, Daniel, Milosavljevic, Milos, and Spitkovsky, Anatoly. A FLUX ROPE NETWORK AND PARTICLE ACCELERATION IN THREEDIMENSIONAL RELATIVISTIC MAGNETIC RECONNECTION. United States: N. p., 2013.
Web. doi:10.1088/0004637X/774/1/41.
Kagan, Daniel, Milosavljevic, Milos, & Spitkovsky, Anatoly. A FLUX ROPE NETWORK AND PARTICLE ACCELERATION IN THREEDIMENSIONAL RELATIVISTIC MAGNETIC RECONNECTION. United States. doi:10.1088/0004637X/774/1/41.
Kagan, Daniel, Milosavljevic, Milos, and Spitkovsky, Anatoly. Sun .
"A FLUX ROPE NETWORK AND PARTICLE ACCELERATION IN THREEDIMENSIONAL RELATIVISTIC MAGNETIC RECONNECTION". United States.
doi:10.1088/0004637X/774/1/41.
@article{osti_22133961,
title = {A FLUX ROPE NETWORK AND PARTICLE ACCELERATION IN THREEDIMENSIONAL RELATIVISTIC MAGNETIC RECONNECTION},
author = {Kagan, Daniel and Milosavljevic, Milos and Spitkovsky, Anatoly},
abstractNote = {We investigate magnetic reconnection and particle acceleration in relativistic pair plasmas with threedimensional particleincell simulations of a kineticscale current sheet in a periodic geometry. We include a guide field that introduces an inclination between the reconnecting field lines and explore outsideofthecurrent sheet magnetizations that are significantly below those considered by other authors carrying out similar calculations. Thus, our simulations probe the transitional regime in which the magnetic and plasma pressures are of the same order of magnitude. The tearing instability is the dominant mode in the current sheet for all guide field strengths, while the linear kink mode is less important even without the guide field, except in the lower magnetization case. Oblique modes seem to be suppressed entirely. In its nonlinear evolution, the reconnection layer develops a network of interconnected and interacting magnetic flux ropes. As smaller flux ropes merge into larger ones, the reconnection layer evolves toward a threedimensional, disordered state in which the resulting flux rope segments contain magnetic substructure on plasma skin depth scales. Embedded in the flux ropes, we detect spatially and temporally intermittent sites of dissipation reflected in peaks in the parallel electric field. Magnetic dissipation and particle acceleration persist until the end of the simulations, with simulations with higher magnetization and lower guide field strength exhibiting greater and faster energy conversion and particle energization. At the end of our largest simulation, the particle energy spectrum attains a tail extending to high Lorentz factors that is best modeled with a combination of two additional thermal components. We confirm that the primary energization mechanism is acceleration by the electric field in the Xline region. The highestenergy positrons (electrons) are moderately beamed with median angles {approx}30 DegreeSign 40 DegreeSign relative to (the opposite of) the direction of the initial current density, but we speculate that reconnection in more highly magnetized plasmas would give rise to stronger beaming. Finally, we discuss the implications of our results for macroscopic reconnection sites, and which of our results may be expected to hold in systems with higher magnetizations.},
doi = {10.1088/0004637X/774/1/41},
journal = {Astrophysical Journal},
number = 1,
volume = 774,
place = {United States},
year = {Sun Sep 01 00:00:00 EDT 2013},
month = {Sun Sep 01 00:00:00 EDT 2013}
}

Threedimensional prominencehosting magnetic configurations: Creating a helical magnetic flux rope
The magnetic configuration hosting prominences and their surrounding coronal structure is a key research topic in solar physics. Recent theoretical and observational studies strongly suggest that a helical magnetic flux rope is an essential ingredient to fulfill most of the theoretical and observational requirements for hosting prominences. To understand flux rope formation details and obtain magnetic configurations suitable for future prominence formation studies, we here report on threedimensional isothermal magnetohydrodynamic simulations including finite gas pressure and gravity. Starting from a magnetohydrostatic corona with a linear forcefree bipolar magnetic field, we follow its evolution when introducing vortex flows around the mainmore » 
Dualspacecraft reconstruction of a threedimensional magnetic flux rope at the Earth's magnetopause
We present the first results of a data analysis method, developed by Sonnerup and Hasegawa (2011), for reconstructing threedimensional (3D), magnetohydrostatic structures from data taken as two closely spaced satellites traverse the structures. The method is applied to a magnetic flux transfer event (FTE), which was encountered on 27 June 2007 by at least three (THC, THD, and THE) of the five THEMIS probes near the subsolar magnetopause. The FTE was sandwiched between two oppositely directed reconnection jets under a southward interplanetary magnetic field condition, consistent with its generation by multiple Xline reconnection. The recovered 3D field indicates that amore »Cited by 3 
The relation between reconnected flux, the parallel electric field, and the reconnection rate in a threedimensional kinetic simulation of magnetic reconnection
We investigate the distribution of parallel electric fields and their relationship to the location and rate of magnetic reconnection in a large particleincell simulation of 3D turbulent magnetic reconnection with open boundary conditions. The simulation's guide field geometry inhibits the formation of simple topological features such as null points. Therefore, we derive the location of potential changes in magnetic connectivity by finding the field lines that experience a large relative change between their endpoints, i.e., the quasiseparatrix layer. We find a good correspondence between the locus of changes in magnetic connectivity or the quasiseparatrix layer and the map of largemore » 
MAGNETOHYDRODYNAMIC SIMULATIONS OF RECONNECTION AND PARTICLE ACCELERATION: THREEDIMENSIONAL EFFECTS
Magnetic fields can change their topology through a process known as magnetic reconnection. This process in not only important for understanding the origin and evolution of the largescale magnetic field, but is seen as a possibly efficient particle accelerator producing cosmic rays mainly through the firstorder Fermi process. In this work we study the properties of particle acceleration inserted in reconnection zones and show that the velocity component parallel to the magnetic field of test particles inserted in magnetohydrodynamic (MHD) domains of reconnection without including kinetic effects, such as pressure anisotropy, the Hall term, or anomalous effects, increases exponentially. Also,more »