Cold Ionospheric Ions in the Magnetic Reconnection Outflow Region

2017 ◽  
Vol 122 (10) ◽  
pp. 10,194-10,202 ◽  
Author(s):  
W. Y. Li ◽  
M. André ◽  
Yu. V. Khotyaintsev ◽  
A. Vaivads ◽  
S. A. Fuselier ◽  
...  
Keyword(s):  
Magnetic Reconnection ◽  
Outflow Region

scholarly journals Electron pitch angle distribution during magnetic reconnection diffusion region observations in the Earth's magnetotail

2012 ◽  
Vol 30 (1) ◽  
pp. 109-117 ◽  
Author(s):  
A. L. Borg ◽  
M. G. G. T. Taylor ◽  
J. P. Eastwood
Keyword(s):  
Magnetic Reconnection ◽  
Electron Flux ◽  
Diffusion Region ◽  
Angle Distribution ◽  
Ion Diffusion ◽  
Electron Field ◽  
Outflow Region ◽  
The Magnetic Field ◽  
Case Basis ◽  
Magnetotail Current Sheet

Abstract. The Earth's magnetosphere provides an excellent laboratory for magnetic reconnection research. In particular, the magnetotail current sheet that is formed between the interface of the similar Northern and Southern Hemispheres of the magnetotail provides a relatively stable symmetric reconnection configuration that can be used to study basic aspects of the reconnection process. Of particular importance is the manner in which electrons are processed by the reconnection. Simulations and satellite data analyses of the ion diffusion region have suggested that the fluxes of electrons in the inflow regions of reconnection are greater in the directions parallel and anti-parallel to the magnetic field (field-aligned) whereas the electron flux in the outflow region is distributed more isotropically. However, this has only been studied experimentally on a case-by-case basis. In this paper, we investigate this claim by analyzing the degree of bulk electron field alignment in the outflow and inflow regions during encounters of the magnetic reconnection ion diffusion region by the Cluster spacecraft in the years 2001–2006. We demonstrate that while the median electron flux in the inflow region is indeed more field aligned than in the outflow region during some ion diffusion region encounters, the variation of the signature across events is so large that it cannot be said to be a general feature of magnetic reconnection in the Earth's magnetotail.

scholarly journals Magnetic islands formed due to the Kelvin‐Helmholtz instability in the outflow region of collisionless magnetic reconnection

2015 ◽  
Vol 42 (18) ◽  
pp. 7282-7286 ◽  
Author(s):  
Can Huang ◽  
Quanming Lu ◽  
Fan Guo ◽  
Mingyu Wu ◽  
Aimin Du ◽  
...  
Keyword(s):  
Magnetic Reconnection ◽  
Magnetic Islands ◽  
Helmholtz Instability ◽  
Outflow Region

MMS observations of electron firehose fluctuations in the magnetic reconnection outflow

2021 ◽  
Author(s):  
Giulia Cozzani ◽  
Yuri Khotyaintsev ◽  
Daniel Graham ◽  
Mats André
Keyword(s):  
Energy Conversion ◽  
Electron Temperature ◽  
Magnetic Reconnection ◽  
Diffusion Region ◽  
Temperature Anisotropy ◽  
Plasma Dynamics ◽  
Background Magnetic Field ◽  
Outflow Region ◽  
Reconnection Site

<p>Plasma waves and instabilities driven by temperature anisotropies are known to play a significant role in plasma dynamics, scattering the particles and affecting particle heating and energy conversion between the electromagnetic fields and the particles. Among these instabilities, the electron firehose instability is driven by electron temperature anisotropy T<sub>e,</sub> > T<sub>e,perp</sub> (with respect to the background magnetic field) and produce nonpropagating oblique modes. </p><p>Magnetic reconnection is characterized by regions of enhanced temperature anisotropy that could drive instabilities - including the electron firehose instability - affecting the particle dynamics and the energy conversion of the process. Yet, the electron firehose instability and its role in the reconnection process is still rather unexplored, especially with in situ measurements. </p><p>We report MMS observations of electron firehose fluctuations observed in the exhaust region of a reconnection site in the magnetotail. The fluctuations are observed in the Earthward outflow relatively close (less than 2 d<sub>i</sub> distance) to the electron diffusion region (EDR). While the characteristics of the fluctuations are compatible with oblique electron firehose fluctuations, the associated firehose instability threshold is not exceeded in the interval where the fluctuations are observed. However, the threshold is exceeded in the EDR. The wave analysis in the EDR suggests that the firehose instability could be active at the reconnection site. We suggest that the firehose fluctuations observed in the outflow region may have been originated at the EDR, where the electron temperature anisotropy exceeds the threshold values, and then advected in the outflow region.</p>

Turbulence-driven magnetic reconnection in the magnetosheath downstream of a quasi-parallel shock：a three-dimensional global hybrid simulation

2020 ◽  
Author(s):  
Quanming Lu ◽  
Huanyu Wang ◽  
Xueyi Wang
Keyword(s):  
Magnetic Reconnection ◽  
Electromagnetic Waves ◽  
High Speed ◽  
Three Dimensional ◽  
Hybrid Simulation ◽  
Bow Shock ◽  
Ion Flow ◽  
Current Sheets ◽  
The Earth ◽  
Outflow Region

<p>Satellite observations with high-resolution measurements have demonstrated the existence of intermittent current sheets and occurrence of magnetic reconnection in a quasi-parallel magnetosheath behind the terrestrial bow shock. In this Letter, by performing a three-dimensional (3-D) global hybrid simulation, we investigated the characteristics of the quasi-parallel magnetosheath of the bow shock, which is formed due to the interaction of the solar wind with the earth’s magnetosphere. Current sheets with widths of several ion inertial lengths are found to be produced in the magnetosheath after the upstream large amplitude electromagnetic waves penetrate through the shock and are then compressed in the downstream. Magnetic reconnection consequently occurs in these current sheets, where high-speed ion flow jets are identified in the outflow region. Simultaneously, flux ropes with the extension (along the   direction) of about several earth’s radii are also observed. Our simulation shed new insight on the mechanism for the occurrence of magnetic reconnection in the quasi-parallel shocked magnetosheath.</p>

scholarly journals Separatrix regions of magnetic reconnection at the magnetopause

2009 ◽  
Vol 27 (10) ◽  
pp. 4039-4056 ◽  
Author(s):  
T. Lindstedt ◽  
Yu. V. Khotyaintsev ◽  
A. Vaivads ◽  
M. André ◽  
R. C. Fear ◽  
...  
Keyword(s):  
Magnetic Reconnection ◽  
Electric Fields ◽  
Strong Field ◽  
Potential Drop ◽  
Current Layer ◽  
Dayside Magnetopause ◽  
Outflow Region ◽  
Strong Electric Fields ◽  
Using Data ◽  
Electric Fields And Currents

Abstract. Using data from the four Cluster spacecraft we study the separatrix regions of magnetic reconnection sites at the dayside magnetopause under conditions when reconnection is occurring in the magnetopause current layer which separates magnetosheath plasma from the hot magnetospheric plasma sheet. We define the separatrix region as the region between the separatrix – the first field line opened by reconnection – and the reconnection jet (outflow region). We analyze eight separatrix region crossings on the magnetospheric side of the magnetopause and present detailed data for two of the events. We show that characteristic widths of the separatrix regions are of the order of ten ion inertial lengths at the magnetopause. Narrow separatrix regions with widths comparable to a few ion inertial lengths are rare. We show that inside the separatrix region there is a density cavity which sometimes has complex internal structure with multiple density dips. Strong electric fields exist inside the separatrix regions and the electric potential drop across the regions can be up to several kV. On the magnetosheath side of the region there is a density gradient with strong field aligned currents. The observed strong electric fields and currents inside the separatrix region can be important for a local energization of ions and electrons, particularly of ionospheric origin, as well as for magnetosphere-ionosphere coupling.

scholarly journals Ion Bernstein waves in the magnetic reconnection region

2016 ◽  
Vol 34 (1) ◽  
pp. 85-89 ◽  
Author(s):  
Y. Narita ◽  
R. Nakamura ◽  
W. Baumjohann ◽  
K.-H. Glassmeier ◽  
U. Motschmann ◽  
...  
Keyword(s):  
Magnetic Reconnection ◽  
Energy Spectra ◽  
Reconnection Region ◽  
Bernstein Waves ◽  
Outflow Region ◽  
The Mean ◽  
Using Data ◽  
First Time ◽  
Proton Gyrofrequency ◽  
Good Agreement

Abstract. Four-dimensional energy spectra and a diagram for dispersion relations are determined for the first time in a magnetic reconnection region in the magnetotail using data from four-spacecraft measurements by the Cluster mission on a spatial scale of 200 km, about 0.1 ion inertial lengths. The energy spectra are anisotropic with an extension in the perpendicular direction and axially asymmetric with respect to the mean magnetic field. The dispersion diagram in the plasma rest frame is in reasonably good agreement with the ion Bernstein waves at the second and higher harmonics of the proton gyrofrequency. Perpendicular-propagating ion Bernstein waves likely exist in an outflow region of magnetic reconnection, which may contribute to bifurcation of the current sheet in the outflow region.

A large rotating structure around AB Doradus A at VLBI scale

2019 ◽  
Vol 15 (S354) ◽  
pp. 189-194
Author(s):  
J. B. Climent ◽  
J. C. Guirado ◽  
R. Azulay ◽  
J. M. Marcaide
Keyword(s):  
Magnetic Reconnection ◽  
Main Sequence ◽  
Complex Structure ◽  
Main Sequence Star ◽  
Polar Cap ◽  
Vlbi Observations ◽  
Rotating Structure ◽  
Source Structure ◽  
Expected Position

AbstractWe report the results of three VLBI observations of the pre-main-sequence star AB Doradus A at 8.4 GHz. With almost three years between consecutive observations, we found a complex structure at the expected position of this star for all epochs. Maps at epochs 2007 and 2010 show a double core-halo morphology while the 2013 map reveals three emission peaks with separations between 5 and 18 stellar radii. Furthermore, all maps show a clear variation of the source structure within the observing time. We consider a number of hypothesis in order to explain such observations, mainly: magnetic reconnection in loops on the polar cap, a more general loop scenario and a close companion to AB Dor A.

Sign in / Sign up

Export Citation Format

Share Document