GPS Scintillations and TEC Variations in Association with A Polar Cap Arc

Author(s):  
Yong Wang ◽  
Zheng Cao ◽  
Zan‐Yang Xing ◽  
Qing‐He Zhang ◽  
P. T. Jayachandran ◽  
...  
Keyword(s):  
2017 ◽  
Vol 7 ◽  
pp. A23 ◽  
Author(s):  
Yaqi Jin ◽  
Jøran I. Moen ◽  
Kjellmar Oksavik ◽  
Andres Spicher ◽  
Lasse B.N. Clausen ◽  
...  
Keyword(s):  

2021 ◽  
Author(s):  
Yong Wang ◽  
Zheng Cao ◽  
Zan-Yang Xing ◽  
Qing-He Zhang ◽  
Periyadan T. Jayachandran ◽  
...  

<p>The first example of a polar cap arc producing clear amplitude and phase scintillations in the GPS L-band is presented using observations from an all-sky imager and a GPS receiver at Resolute Bay and the SuperDARN Inuvik radar. The polar cap arc moved quickly from the dusk-side to the midnight auroral oval at a speed of ~700 m/s, as revealed by all-sky 557.7 nm and 630.0 nm images. When it intersected the ray path of GPS signals, both amplitude and phase scintillations appeared, which is very different from previous results. Moreover, the scintillations were precisely determined through power spectral analysis. We propose that the strong total electron content (TEC) enhancement (~6 TECU) and flow shears in association with the polar cap arc were causing the scintillations. It provides instructive evidence for the existence of polar cap arc scintillations that may be harmful for satellite applications even through L-band signals.</p>


2019 ◽  
Vol 15 (S354) ◽  
pp. 189-194
Author(s):  
J. B. Climent ◽  
J. C. Guirado ◽  
R. Azulay ◽  
J. M. Marcaide

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.


2020 ◽  
Vol 7 (8) ◽  
Author(s):  
Erxiao Liu ◽  
Hongqiao Hu ◽  
Jianjun Liu ◽  
Lei Qiao

2013 ◽  
Vol 3 ◽  
pp. A02 ◽  
Author(s):  
Jøran Moen ◽  
Kjellmar Oksavik ◽  
Lucilla Alfonsi ◽  
Yvonne Daabakk ◽  
Vineenzo Romano ◽  
...  
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2011 ◽  
Vol 29 (8) ◽  
pp. 1355-1363 ◽  
Author(s):  
H. T. Cai ◽  
F. Yin ◽  
S. Y. Ma ◽  
I. W. McCrea

Abstract. In this paper, we present observational evidence for the trans-polar propagation of large-scale Traveling Ionospheric Disturbances (TIDs) from their nightside source region to the dayside. On 13 February 2001, the 32 m dish of EISCAT Svalbard Radar (ESR) was directing toward the geomagnetic pole at low elevation (30°) during the interval 06:00–12:00 UT (MLT ≈ UT + 3 h), providing an excellent opportunity to monitor the ionosphere F-region over the polar cap. The TIDs were first detected by the ESR over the dayside north polar cap, propagating equatorward, and were subsequently seen by the mainland UHF radar at auroral latitudes around geomagnetic local noon. The propagation properties of the observed ionization waves suggest the presence of a moderately large-scale TIDs, propagating across the northern polar cap from the night-time auroral source during substorm conditions. Our results agree with the theoretical simulations by Balthazor and Moffett (1999) in which poleward-propagating large-scale traveling atmospheric disturbances were found to be self-consistently driven by enhancements in auroral heating.


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