Orientation of X lines in asymmetric magnetic reconnection—Mass ratio dependency

Liu, Yi‐Hsin; Hesse, Michael; Кузнецова, М. М.

doi:10.1002/2015ja021324

Cited by 23 publications

(63 citation statements)

References 58 publications

(74 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As observed in asymmetric simulations (see, e.g., Pritchett, ; Liu et al, ; Shay et al, ), including those presented here, the current sheets and parallel electric field are skewed toward the magnetosphere side of the layer. Figure maps the curlometer (top) and particle (middle) J M current, and the smoothed parallel electric field (bottom).…”

Section: Mms Observationssupporting

confidence: 74%

“…To numerically simulate M for the asymmetric case, we use the VPIC code (Bowers et al, ) with two slightly different configurations. The setup for the 3‐D guide field simulation is as outlined in Liu et al (). The magnetic profile is given by

boldB = B_{0} ((), 0.5 + S) {\overset{truê}{boldx}}_{0} + B_{y 0} {\overset{truê}{boldy}}_{0}

, with S = tanh ( z / λ ), where λ is the initial half‐width of the current sheet.…”

Section: Pic Simulation Setupmentioning

confidence: 99%

“…The boundary conditions are periodic in x and y , and reflecting for particles and conducting for fields in the z direction. There are 150 particles per cell, and λ = 0.8 d i . The nature of the perturbation is chosen to avert early formation of tearing instabilities, with a peak value δB z = 0.05 B 0 (for details, see Liu et al, ). To improve particle statistics in the 3‐D guide field case, we have averaged all simulation quantities over 1,000 time steps, where each time step is 0.002 Ω c,i −1 .…”

Section: Pic Simulation Setupmentioning

confidence: 99%

See 2 more Smart Citations

Violation of Field Line Conservation and Associated Spatial Scales in Particle‐in‐Cell Simulations and MMS Data

et al. 2018

Self Cite

View full text Add to dashboard Cite

For the first time, space flight technology exists to detect, in situ, violation of magnetic field line conservation. The violation of magnetic line conservation on scales smaller than the system size is a necessary and sufficient condition for finite magnetic field reconnection. We demonstrate that violation of line conservation produces a detectable, structured signature both in particle‐in‐cell simulations of reconnection and in data from the Magnetospheric Multi‐Scale mission. In particle‐in‐cell simulations of asymmetric reconnection, the quantity—which we call M—that identifies this violation achieves significant values in electron skin depth‐scale layers that extend away from the separator, with higher values emerging on the low‐density, high‐magnetic‐field side of the current sheet. At the separator, M owes largely to perpendicular gradients in the parallel electric field, while it attains its highest values away from the separator in dispersed, layered structures associated with gradients in the perpendicular nonideal electric field and electron transport. Sub‐ion scale bipolar forms of the quantity also appear further from the separator. In two MMS burst data intervals detecting the electron diffusion region, we find that M exceeds measurement uncertainties both at the separator and near the separatrices. One interval has highly sheared reconnecting fields and the other a stronger guide field. For one event, we determine the location and scale of M and the inner electron diffusion region relative to electron outflows and the magnetic separatrices. The measure can therefore serve as a potent diagnostic for magnetic reconnection in space measurements.

show abstract

Section: Mms Observationssupporting

confidence: 74%

boldB = B_{0} ((), 0.5 + S) {\overset{truê}{boldx}}_{0} + B_{y 0} {\overset{truê}{boldy}}_{0}

, with S = tanh ( z / λ ), where λ is the initial half‐width of the current sheet.…”

Section: Pic Simulation Setupmentioning

confidence: 99%

Section: Pic Simulation Setupmentioning

confidence: 99%

See 1 more Smart Citation

Violation of Field Line Conservation and Associated Spatial Scales in Particle‐in‐Cell Simulations and MMS Data

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…An M component of the magnetic field (a guide field) may also be present, along with the all‐important reconnection electric field component. However, for the asymmetric conditions typical at the magnetopause, the invariant direction and the X line may be differently oriented (for a brief overview, see Liu et al, ). This L ‐ M ‐ N system is similar to, but not identical to, the boundary normal system defined by Russell and Elphic ().…”

Section: Introductionmentioning

confidence: 99%

Determining L‐M‐N Current Sheet Coordinates at the Magnetopause From Magnetospheric Multiscale Data

et al. 2018

View full text Add to dashboard Cite

We discuss methods to determine L‐M‐N coordinate systems for current sheet crossings observed by the Magnetospheric Multiscale (MMS) spacecraft mission during ongoing reconnection, where eL is the direction of the reconnecting component of the magnetic field, B, and eN is normal to the magnetopause. We present and test a new hybrid method, with eL estimated as the maximum variance direction of B (MVAB) and eN as the direction of maximum directional derivative of B, and then adjust these directions to be perpendicular. In the best case, only small adjustment is needed. Results from this method, applied to an MMS crossing of the dayside magnetopause at 1305:45 UT on 16 October 2015, are discussed and compared with those from other methods for which eN is obtained by other means. Each of the other evaluations can be combined with eL from MVAB in a generalized hybrid approach to provide an L‐M‐N system. The quality of the results is judged by eigenvalue ratios, constancy of directions using different data segments and methods, and expected sign and magnitude of the normal component of B. For this event, the hybrid method appears to produce eN accurate to within less than 10°. We discuss variance analysis using the electric current density, J, or the J × B force, which yield promising results, and minimum Faraday residue analysis and MVAB alone, which can be useful for other events. We also briefly discuss results from our hybrid method and MVAB alone for a few other MMS reconnection events.

show abstract

“…Simulations have also been done for the force-free Harris sheet, but usually with initial distribution functions that are Maxwell-Boltzmann distributions shifted by the macroscopic bulk flow of the particle species (e.g. [57][58][59][60][61][62][63]. Other authors used the bi-Maxwellian selfconsistent equilibrium distribution function for linear forcefree fields (e.g [34,35,39]) to initialise their simulations (e.g.…”

Section: Discussionmentioning

confidence: 99%

Collisionless current sheet equilibria

Neukirch

Wilson

Allanson

2017

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

Current sheets are important for the structure and dynamics of many plasma systems. In space and astrophysical plasmas they play a crucial role in activity processes, for example by facilitating the release of magnetic energy via processes such as magnetic reconnection. In this contribution we will focus on collisionless plasma systems. A sensible first step in any investigation of physical processes involving current sheets is to find appropriate equilibrium solutions. The theory of collisionless plasma equilibria is well established, but over the past few years there has been a renewed interest in finding equilibrium distribution functions for collisionless current sheets with particular properties, for example for cases where the current density is parallel to the magnetic field (force-free current sheets). This interest is due to a combination of scientific curiosity and potential applications to space and astrophysical plasmas. In this paper we will give an overview of some of the recent developments, discuss their potential applications and address a number of open questions.

show abstract

Orientation of X lines in asymmetric magnetic reconnection—Mass ratio dependency

Cited by 23 publications

References 58 publications

Violation of Field Line Conservation and Associated Spatial Scales in Particle‐in‐Cell Simulations and MMS Data

Violation of Field Line Conservation and Associated Spatial Scales in Particle‐in‐Cell Simulations and MMS Data

Determining L‐M‐N Current Sheet Coordinates at the Magnetopause From Magnetospheric Multiscale Data

Collisionless current sheet equilibria

Contact Info

Product

Resources

About