The Acceleration Region of Stable Auroral Arcs

2012 ◽  
pp. 227-239 ◽  
Author(s):  
T. Karlsson
Keyword(s):  
Acceleration Region ◽  
Auroral Arcs

scholarly journals An Auroral Alfvén Wave Cascade

2021 ◽  
Vol 8 ◽  
Author(s):  
C. C. Chaston
Keyword(s):  
Space Plasma ◽  
Alfven Waves ◽  
Alfven Wave ◽  
Alfvén Waves ◽  
Acceleration Region ◽  
Electrical Currents ◽  
Auroral Acceleration Region ◽  
Field Lines ◽  
Auroral Arcs

Folding, kinking, curling and vortical optical forms are distinctive features of most bright auroral displays. These forms are symptomatic of non-linear forcing of the plasma above auroral arcs resulting from the intensification of electrical currents and Alfvén waves along high-latitude geomagnetic field-lines during periods of disturbed space weather. Electrons accelerated to energies sufficient to carry these currents impact the atmosphere and drive visible emission with spatial structure and dynamics that replicate the morphology and time evolution of the plasma region where the acceleration occurs. Movies of active auroral displays, particularly when combined with conjugate in-situ fields and plasma measurements, therefore capture the physics of a driven, non-linearly evolving space plasma system. Here a perspective emphasizing the utility of combining in-situ measurements through the auroral acceleration region with high time and spatial resolution auroral imaging for the study of space plasma turbulence is presented. It is demonstrated how this special capacity reveals the operation of a cascade of vortical flows and currents through the auroral acceleration region regulated by the physics of Alfvén waves similar to that thought to operate in the Solar wind.

scholarly journals Active auroral arc powered by accelerated electrons from very high altitudes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shun Imajo ◽  
Yoshizumi Miyoshi ◽  
Yoichi Kazama ◽  
Kazushi Asamura ◽  
Iku Shinohara ◽  
...  
Keyword(s):  
Potential Drop ◽  
Optical Observations ◽  
High Angular Resolution ◽  
Polar Regions ◽  
Acceleration Region ◽  
Static Electric Field ◽  
Resolution Electron ◽  
Low Altitude ◽  
Auroral Arcs ◽  
Very High

AbstractBright, discrete, thin auroral arcs are a typical form of auroras in nightside polar regions. Their light is produced by magnetospheric electrons, accelerated downward to obtain energies of several kilo electron volts by a quasi-static electric field. These electrons collide with and excite thermosphere atoms to higher energy states at altitude of ~ 100 km; relaxation from these states produces the auroral light. The electric potential accelerating the aurora-producing electrons has been reported to lie immediately above the ionosphere, at a few altitudes of thousand kilometres1. However, the highest altitude at which the precipitating electron is accelerated by the parallel potential drop is still unclear. Here, we show that active auroral arcs are powered by electrons accelerated at altitudes reaching greater than 30,000 km. We employ high-angular resolution electron observations achieved by the Arase satellite in the magnetosphere and optical observations of the aurora from a ground-based all-sky imager. Our observations of electron properties and dynamics resemble those of electron potential acceleration reported from low-altitude satellites except that the acceleration region is much higher than previously assumed. This shows that the dominant auroral acceleration region can extend far above a few thousand kilometres, well within the magnetospheric plasma proper, suggesting formation of the acceleration region by some unknown magnetospheric mechanisms.

Monitoring of the Electron-Acceleration Region with Auroral Kilometric Radiation

2020 ◽  
Vol 60 (5) ◽  
pp. 538-546
Author(s):  
D. V. Chugunin ◽  
A. A. Chernyshov ◽  
I. L. Moiseenko ◽  
M. E. Viktorov ◽  
M. M. Mogilevsky
Keyword(s):  
Electron Acceleration ◽  
Acceleration Region ◽  
Auroral Kilometric Radiation

scholarly journals Spectral observations of FUV auroral arcs and comparison with inverted-V precipitating electrons

2010 ◽  
Vol 115 (A9) ◽  
pp. n/a-n/a ◽  
Author(s):  
C. N. Lee ◽  
K. W. Min ◽  
J.-J. Lee ◽  
G. K. Parks ◽  
M. O. Fillingim ◽  
...  
Keyword(s):  
Auroral Arcs

Development of Gas Scintillation Proportional Counter

1999 ◽  
Vol 09 (03n04) ◽  
pp. 169-174
Author(s):  
N. Shigeoka ◽  
K. Mutaguchi ◽  
Y. Nakanishi ◽  
Y. Ito ◽  
T. Mukoyama ◽  
...  
Keyword(s):  
Proportional Counter ◽  
Pulse Height ◽  
Acceleration Region ◽  
X Ray ◽  
Gaussian Profile ◽  
Profile Fitting ◽  
Fitting Method

The properties of gas scintillation proportional counter are investigated for Mn K x-ray spectra. The pulse-height spectra are strongly affected by changing of the value of a potential V 2 in the acceleration region and analyzed by the Gaussian profile fitting method.

scholarly journals Dawn Auroral Breakup at Saturn Initiated by Auroral Arcs: UVIS/Cassini Beginning of Grand Finale Phase

2017 ◽  
Vol 122 (12) ◽  
pp. 12,111-12,119 ◽  
Author(s):  
A. Radioti ◽  
D. Grodent ◽  
Z. H. Yao ◽  
J.-C. Gérard ◽  
S. V. Badman ◽  
...  
Keyword(s):  
Auroral Breakup ◽  
Auroral Arcs

scholarly journals Species dependent energies in upward directed ion beams over auroral arcs as observed with FAST TEAMS

1998 ◽  
Vol 25 (12) ◽  
pp. 2029-2032 ◽  
Author(s):  
E. Möbius ◽  
L. Tang ◽  
L. M. Kistler ◽  
M. Popecki ◽  
E. J. Lund ◽  
...  
Keyword(s):  
Ion Beams ◽  
Auroral Arcs
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