scholarly journals Ion acceleration dependence on magnetic shear angle in dayside magnetopause reconnection

2015 ◽  
Vol 120 (9) ◽  
pp. 7255-7269 ◽  
Author(s):  
S. K. Vines ◽  
S. A. Fuselier ◽  
K. J. Trattner ◽  
S. M. Petrinec ◽  
J. F. Drake
Keyword(s):  
Shear Angle ◽  
Ion Acceleration ◽  
Magnetic Shear ◽  
Dayside Magnetopause ◽  
Magnetopause Reconnection

scholarly journals Double Star TC-1 observations of component reconnection at the dayside magnetopause: a preliminary study

2005 ◽  
Vol 23 (8) ◽  
pp. 2889-2895 ◽  
Author(s):  
Z. Y. Pu ◽  
C. J. Xiao ◽  
X. G. Zhang ◽  
Z. Y. Huang ◽  
S. Y. Fu ◽  
...  
Keyword(s):  
Double Star ◽  
Flow Reversal ◽  
Low Latitude ◽  
Magnetic Shear ◽  
Guide Field ◽  
Dayside Magnetopause ◽  
Preliminary Study ◽  
Reconnection Site ◽  
Quadrupolar Field

Abstract. In spring 2004 Double Star TC-1 measured a number of reconnection signatures at the dayside low-latitude magnetopause (MP) when there was a notable By component in the magnetosheath. In a number of events we can show that reconnection was operating nearby TC-1 in the subsolar MP region. In this paper we describe three representative events: (a) event on 21 March 2004 in which the reconnection site can be remotely monitored, the spacecraft was passing by the X-line; (b) event on 12 March 2004 in which TC-1 observed the magnetospheric part of the quadrupolar field, together with a consistent flow reversal; (c) event on 26 March 2004 which occurred for northward IMF, TC-1 observed a reversal of vy across the equatorial MP. In these events the shear angles across the MP were considerably smaller than 180°; a noticeable guide field was present. These observations are consistent with near equatorial component merging, suggesting that component reconnection preferably occurs at the dayside low-latitude MP. There is evidence that when a pronounced magnetic shear across the MP exists in the By component, reconnection may operate at the dayside low-latitude MP for northward IMF Bz.

Hybrid-Vlasov modelling of three-dimensional dayside magnetopause reconnection

2021 ◽  
Author(s):  
Yann Pfau-Kempf ◽  
Minna Palmroth ◽  
Andreas Johlander ◽  
Lucile Turc ◽  
Markku Alho ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Reconnection ◽  
Three Dimensional ◽  
Meridional Plane ◽  
Kinetic Behavior ◽  
Dayside Magnetopause ◽  
Field Junction ◽  
First Time ◽  
Kinetic Instabilities ◽  
Magnetopause Reconnection

<p>Dayside magnetic reconnection at the magnetopause, which is a major driver of space weather, is studied for the first time in a three-dimensional (3D) realistic setup using the Vlasiator hybrid-Vlasov kinetic model. A noon–midnight meridional plane simulation is extended in the dawn–dusk direction to cover 7 Earth radii. The southward interplanetary magnetic field causes magnetic reconnection to occur at the subsolar magnetopause. Perturbations arising from kinetic instabilities in the magnetosheath appear to modulate the reconnection. Its characteristics are consistent with multiple, bursty, and patchy magnetopause reconnection. It is shown that the kinetic behavior of the plasma, as simulated by the model, has consequences on the applicability of methods such as the four-field junction to identify and analyse magnetic reconnection in 3D kinetic simulations.</p>

scholarly journals A numerical model of the ionospheric signatures of time-varying magnetic reconnection: III. Quasi-instantaneous convection responses in the Cowley-Lockwood paradigm

2006 ◽  
Vol 24 (3) ◽  
pp. 961-972 ◽  
Author(s):  
S. K. Morley ◽  
M. Lockwood
Keyword(s):  
The Other ◽  
Closed Field ◽  
Time Varying ◽  
Residual Flow ◽  
Numerical Implementation ◽  
Ionospheric Convection ◽  
Dayside Magnetopause ◽  
History Of ◽  
Closed Field Line ◽  
Magnetopause Reconnection

Abstract. Using a numerical implementation of the cowlock92 model of flow excitation in the magnetosphere-ionosphere (MI) system, we show that both an expanding (on a ~12-min timescale) and a quasi-instantaneous response in ionospheric convection to the onset of magnetopause reconnection can be accommodated by the Cowley-Lockwood conceptual framework. This model has a key feature of time dependence, necessarily considering the history of the coupled MI system. We show that a residual flow, driven by prior magnetopause reconnection, can produce a quasi-instantaneous global ionospheric convection response; perturbations from an equilibrium state may also be present from tail reconnection, which will superpose constructively to give a similar effect. On the other hand, when the MI system is relatively free of pre-existing flow, we can most clearly see the expanding nature of the response. As the open-closed field line boundary will frequently be in motion from such prior reconnection (both at the dayside magnetopause and in the cross-tail current sheet), it is expected that there will usually be some level of combined response to dayside reconnection.

scholarly journals Dayside Magnetopause Reconnection: Its Dependence on Solar Wind and Magnetosheath Conditions

2019 ◽  
Vol 124 (11) ◽  
pp. 8778-8787
Author(s):  
D. Koga ◽  
W. D. Gonzalez ◽  
V. M. Souza ◽  
F. R. Cardoso ◽  
C. Wang ◽  
...  
Keyword(s):  
Solar Wind ◽  
Dayside Magnetopause ◽  
Magnetopause Reconnection

scholarly journals Magnetic Shear and Nonpotential Energy Evolution of Solar Minimum and the Onset of Solar Cycle 23

2001 ◽  
Vol 203 ◽  
pp. 267-269
Author(s):  
J. Dun ◽  
H. Zhang ◽  
B. Zhang ◽  
R. Li
Keyword(s):  
Solar Cycle ◽  
Relative Number ◽  
Transverse Field ◽  
Active Regions ◽  
Shear Angle ◽  
Magnetic Shear ◽  
Data Set ◽  
Solar Cycle 23 ◽  
Sunspot Relative Number ◽  
The Magnetic Field

Using a 1995-1998 data set of vector magnetograms, the magnetic field flux, shear angle of the transverse field and nonpotential energy of active regions were calculated. The evolution of these parameters were analyzed together with time series of the solar monthly sunspot relative number and area to study their relationships in the ascending phase of solar cycle 23. We find the magnetic flux and nonpotential energy have a good correlation with sunspot relative number and area. But the magnetic shear angle does not develop as above indices.

scholarly journals Locating dayside magnetopause reconnection with exhaust ion distributions

2017 ◽  
Vol 122 (5) ◽  
pp. 5105-5113 ◽  
Author(s):  
J. M. Broll ◽  
S. A. Fuselier ◽  
K. J. Trattner
Keyword(s):  
Ion Distributions ◽  
Dayside Magnetopause ◽  
Magnetopause Reconnection

Orientation of the X-line in asymmetric magnetic reconnection

2016 ◽  
Vol 82 (4) ◽  
Author(s):  
N. Aunai ◽  
M. Hesse ◽  
B. Lavraud ◽  
J. Dargent ◽  
R. Smets
Keyword(s):  
Magnetic Reconnection ◽  
Domain Size ◽  
Shear Angle ◽  
Two Dimensional ◽  
Field Profile ◽  
Reconnection Rate ◽  
Magnetic Shear ◽  
Magnetic Field Profile ◽  
The Earth ◽  
Set Up

Magnetic reconnection can occur in current sheets separating magnetic fields sheared by any angle and of arbitrarily different amplitudes. In such asymmetric and non-coplanar systems, it is not yet understood what the orientation of the X-line will be. Studying how this orientation is determined locally by the reconnection process is important to understand systems such as the Earth magnetopause, where reconnection occurs in regions with large differences in upstream plasma and field properties. This study aims at determining what the local X-line orientation is for different upstream magnetic shear angles in an asymmetric set-up relevant to the Earth’s magnetopause. We use two-dimensional hybrid simulations and vary the simulation plane orientation with regard to the fixed magnetic field profile and search for the plane maximizing the reconnection rate. We find that the plane defined by the bisector of upstream fields maximizes the reconnection rate and this appears not to depend on the magnetic shear angle, domain size or upstream plasma and asymmetries.

The relationship between ELF-VHF waves and magnetic shear at the dayside magnetopause

1996 ◽  
Vol 23 (7) ◽  
pp. 773-776 ◽  
Author(s):  
Z. Zhu ◽  
P. Song ◽  
J. F. Drake ◽  
C. T. Russell ◽  
R. R. Anderson ◽  
...  
Keyword(s):  
Magnetic Shear ◽  
Dayside Magnetopause ◽  
The Relationship

scholarly journals Evidence for transient, local ion foreshocks caused by dayside magnetopause reconnection

2016 ◽  
Vol 34 (11) ◽  
pp. 943-959 ◽  
Author(s):  
Yann Pfau-Kempf ◽  
Heli Hietala ◽  
Steve E. Milan ◽  
Liisa Juusola ◽  
Sanni Hoilijoki ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Interplanetary Magnetic Field ◽  
Ion Beams ◽  
Bow Shock ◽  
Flux Transfer Events ◽  
Dayside Magnetopause ◽  
Flux Transfer ◽  
Push Out ◽  
Magnetopause Reconnection

Abstract. We present a scenario resulting in time-dependent behaviour of the bow shock and transient, local ion reflection under unchanging solar wind conditions. Dayside magnetopause reconnection produces flux transfer events driving fast-mode wave fronts in the magnetosheath. These fronts push out the bow shock surface due to their increased downstream pressure. The resulting bow shock deformations lead to a configuration favourable to localized ion reflection and thus the formation of transient, travelling foreshock-like field-aligned ion beams. This is identified in two-dimensional global magnetospheric hybrid-Vlasov simulations of the Earth's magnetosphere performed using the Vlasiator model (http://vlasiator.fmi.fi). We also present observational data showing the occurrence of dayside reconnection and flux transfer events at the same time as Geotail observations of transient foreshock-like field-aligned ion beams. The spacecraft is located well upstream of the foreshock edge and the bow shock, during a steady southward interplanetary magnetic field and in the absence of any solar wind or interplanetary magnetic field perturbations. This indicates the formation of such localized ion foreshocks.

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