scholarly journals Magnetic reconnection and kinetic waves generated in the Earth's quasi-parallel bow shock

2020 ◽  
Vol 27 (9) ◽  
pp. 092901
Author(s):  
N. Bessho ◽  
L.-J. Chen ◽  
S. Wang ◽  
M. Hesse ◽  
L. B. Wilson ◽  
...  
Keyword(s):  
Magnetic Reconnection ◽  
Bow Shock

scholarly journals Observational Evidence of Magnetic Reconnection in the Terrestrial Foreshock Region

2021 ◽  
Vol 922 (1) ◽  
pp. 56
Author(s):  
K. Jiang ◽  
S. Y. Huang ◽  
H. S. Fu ◽  
Z. G. Yuan ◽  
X. H. Deng ◽  
...  
Keyword(s):  
Magnetic Reconnection ◽  
Direct Evidence ◽  
Bow Shock ◽  
Shock Acceleration ◽  
Diffusive Shock Acceleration ◽  
Strong Energy ◽  
Magnetospheric Multiscale ◽  
Electron Distributions ◽  
Magnetospheric Multiscale Mission ◽  
The Magnetic Field

Abstract Electron heating/acceleration in the foreshock, by which electrons may be energized beyond thermal energies prior to encountering the bow shock, is very important for the bow shock dynamics. And then these electrons would be more easily injected into a process like diffusive shock acceleration. Many mechanisms have been proposed to explain electrons heating/acceleration in the foreshock. Magnetic reconnection is one possible candidate. Taking advantage of the Magnetospheric Multiscale mission, we present two magnetic reconnection events in the dawnside and duskside ion foreshock region, respectively. Super-Alfvénic electron outflow, demagnetization of the electrons and the ions, and crescent electron distributions in the plane perpendicular to the magnetic field are observed in the sub-ion-scale current sheets. Moreover, strong energy conversion from the fields to the plasmas and significant electron temperature enhancement are observed. Our observations provide direct evidence that magnetic reconnection could occur in the foreshock region and heat/accelerate the electrons therein.

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 Observational Evidence of Magnetic Reconnection in the Terrestrial Bow Shock Transition Region

2019 ◽  
Vol 46 (2) ◽  
pp. 562-570 ◽  
Author(s):  
Shan Wang ◽  
Li‐Jen Chen ◽  
Naoki Bessho ◽  
Michael Hesse ◽  
Lynn B. Wilson ◽  
...  
Keyword(s):  
Magnetic Reconnection ◽  
Transition Region ◽  
Observational Evidence ◽  
Bow Shock ◽  
Shock Transition

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.

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