Field-aligned current signatures during the March 13–14, 1989, Great Magnetic Storm

1992 ◽  
Vol 97 (A7) ◽  
pp. 10703 ◽  
Author(s):  
R. Fujii ◽  
H. Fukunishi ◽  
S. Kokubun ◽  
M. Sugiura ◽  
F. Tohyama ◽  
...  
Keyword(s):  
Magnetic Storm ◽  
Field Aligned Current ◽  
Current Signatures

Field-aligned current, convective electric field, and auroral particle measurements during a major magnetic storm

1981 ◽  
Vol 86 (A7) ◽  
pp. 5561 ◽  
Author(s):  
B. M. Shuman ◽  
R. P. Vancour ◽  
M. Smiddy ◽  
N. A. Saflekos ◽  
F. J. Rich
Keyword(s):  
Electric Field ◽  
Magnetic Storm ◽  
Particle Measurements ◽  
Field Aligned Current

Altitudinal comparison of dayside field-aligned current signatures by Viking and DMSP-F7: Intermediate-scale field-aligned current systems

1996 ◽  
Vol 101 (A7) ◽  
pp. 15297-15310 ◽  
Author(s):  
S. Ohtani ◽  
L. G. Blomberg ◽  
P. T. Newell ◽  
M. Yamauchi ◽  
T. A. Potemra ◽  
...  
Keyword(s):  
Intermediate Scale ◽  
Scale Field ◽  
Field Aligned Current ◽  
Current Signatures ◽  
Current Systems

scholarly journals An empirical model of the auroral oval derived from CHAMP field-aligned current signatures – Part 2

2014 ◽  
Vol 32 (6) ◽  
pp. 623-631 ◽  
Author(s):  
C. Xiong ◽  
H. Lühr
Keyword(s):  
Electric Field ◽  
Auroral Oval ◽  
Quadratic Functions ◽  
Optical Observations ◽  
Optimal Delay ◽  
Delay Times ◽  
Field Aligned Current ◽  
The Difference ◽  
Current Signatures ◽  
Good Agreement

Abstract. In this paper we introduce a new model for the location of the auroral oval. The auroral boundaries are derived from small- and medium-scale field-aligned current (FAC) based on the high-resolution CHAMP (CHAllenging Minisatellite Payload) magnetic field observations during the years 2000–2010. The basic shape of the auroral oval is controlled by the dayside merging electric field, Em, and can be fitted well by ellipses at all levels of activity. All five ellipse parameters show a dependence on Em which can be described by quadratic functions. Optimal delay times for the merging electric field at the bow shock are 30 and 15 min for the equatorward and poleward boundaries, respectively. A comparison between our model and the British Antarctic Survey (BAS) auroral model derived from IMAGE (Imager for Magnetopause-to-Aurora Global Exploration) optical observations has been performed. There is good agreement between the two models regarding both boundaries, and the differences show a Gaussian distribution with a width of ±2° in latitude. The difference of the equatorward boundary shows a local-time dependence, which is 1° in latitude poleward in the morning sector and 1° equatorward in the afternoon sector of the BAS model. We think the difference between the two models is caused by the appearance of auroral forms in connection with upward FACs. All information required for applying our auroral oval model (CH-Aurora-2014) is provided.

scholarly journals Extraordinary field-aligned current signatures in Saturn's high-latitude magnetosphere: Analysis of Cassini data during Revolution 89

2010 ◽  
Vol 115 (A10) ◽  
pp. n/a-n/a ◽  
Author(s):  
E. J. Bunce ◽  
S. W. H. Cowley ◽  
D. L. Talboys ◽  
M. K. Dougherty ◽  
L. Lamy ◽  
...  
Keyword(s):  
High Latitude ◽  
Field Aligned Current ◽  
Current Signatures

Interball Observations Of Field Aligned Current Signatures Due To Collisionless Reconnection

1999 ◽  
pp. 687-692 ◽  
Author(s):  
B. Nikutowski ◽  
J. Büchner ◽  
S. Klimov ◽  
A. Petrukovich ◽  
S. Romanov ◽  
...  
Keyword(s):  
Collisionless Reconnection ◽  
Field Aligned Current ◽  
Current Signatures

Azimuthal field signatures associated with magnetosphere-ionosphere coupling in the Jovian magnetosphere: Comparison between Juno observations and theoretical modelling

2021 ◽  
Author(s):  
Aneesah Kamran ◽  
Emma Bunce ◽  
Stanley Cowley ◽  
Jonathan Nichols ◽  
Gabrielle Provan
Keyword(s):  
Magnetic Field ◽  
Northern Hemisphere ◽  
Rotation Axis ◽  
Coupling Model ◽  
Theoretical Modelling ◽  
Jovian Magnetosphere ◽  
Field Aligned Current ◽  
Field Lines ◽  
Current Signatures ◽  
The Magnetic Field

<p>We present a comparison of magnetic field data collected by the NASA Juno spacecraft, with the magnetosphere-ionosphere (MI) coupling model for the Jovian system developed by the University of Leicester. We study the magnetic field of Jupiter, in the Northern Hemisphere, for Perijoves 1-13. By virtue of the offset of the magnetic field to the rotation axis and the subsequent “wobble” of the Juno trajectory in magnetic coordinates, these northern hemisphere portions of PJs 1-13 see the spacecraft traversing the magnetic field lines connecting to the inner, middle, outer and tail regions of the magnetosphere. As such, even away from the close Perijove period, the observations contain evidence of the expected magnetic field perturbations associated with field-aligned currents associated with this fundamental MI coupling. In this study, therefore, we focus on investigating the nature of the field-aligned current signatures evident in the residual azimuthal field (having subtracted the Connerney et al 2018 JRM09 internal magnetic field model) along the magnetic field lines outside of the close periapsides. We map the residual azimuthal field signatures into the ionosphere, and calculate the corresponding ionospheric Pedersen current on an orbit by orbit basis. We compare the magnitude and distribution of these field-aligned current signatures to those expected from the Leicester model, and consider the observed orbit-by-orbit variation as a function of ionospheric colatitude and longitude. We deduce estimates for the field-aligned current densities on auroral field lines for each observation using the Pedersen currents and their distribution in co-latitude, and compare to the previous work of Kotsiaros et al [2019]. We discuss possible reasons for the variations we see, and present the next steps of our broader analysis.</p>

Field-aligned current signatures in the near-tail region: 2. Coupling between the region 1 and the region 2 systems

1990 ◽  
Vol 95 (A11) ◽  
pp. 18913 ◽  
Author(s):  
S. Ohtani ◽  
S. Kokubun ◽  
R. Nakamura ◽  
R. C. Elphic ◽  
C. T. Russell ◽  
...  
Keyword(s):  
Tail Region ◽  
Field Aligned Current ◽  
Current Signatures

scholarly journals Determining the boundaries of the auroral oval from CHAMP field-aligned current signatures – Part 1

2014 ◽  
Vol 32 (6) ◽  
pp. 609-622 ◽  
Author(s):  
C. Xiong ◽  
H. Lühr ◽  
H. Wang ◽  
M. G. Johnsen
Keyword(s):  
Auroral Oval ◽  
Magnetic Activity ◽  
Activity Level ◽  
Magnetic Pole ◽  
Magnetic Field Data ◽  
Functional Relations ◽  
A Value ◽  
Field Aligned Current ◽  
Current Signatures ◽  
Activity Indices

Abstract. In this paper we present the first statistical study on auroral oval boundaries derived from small- and medium-scale field-aligned currents (FACs, < 150 km). The dynamics of both the equatorward and poleward boundaries is deduced from 10 years of CHAMP (CHAllenging Minisatellite Payload) magnetic field data (August 2000–August 2010). The approach for detecting the boundaries from FACs works well under dark conditions. For a given activity level the boundaries form well-defined ellipses around the magnetic pole. The latitudes of the equatorward and poleward boundaries both depend, but in different ways, on magnetic activity. With increasing magnetic activity the equatorward boundary expands everywhere, while the poleward boundary shows on average no dependence on activity around midnight, which seems to be stationary at a value of about 72° Mlat. Functional relations between the latitudes of the boundaries and different magnetic activity indices have been tested. Best results for a linear dependence are derived for both boundaries with the dayside merging electric field. The other indices, like the auroral electrojet (AE) and disturbance storm time (Dst) index, also provide good linear relations but with some caveats. Toward high activity a saturation of equatorwards expansion seems to set in. The locations of the auroral boundaries are practically independent of the level of the solar EUV flux and show no dependence on season.

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