Results 271 to 280 of about 23,252 (283)

Can Throat Auroras Create Polar Cap Patches？

2023
Throat auroras and polar cap patches are common phenomena in the polar ionosphere. An observation campaign was organized, with all-sky imagers at Yellow River Station in Ny-Ålesund in Svalbard, the EISCAT Svalbard Radar, and coordinated low-altitude spacecraft observations.
Duan Zhang, Qinghe Zhang, Kjellmar Oksavik, Tong Xu, Zanyang Xing, Larry Lyons, Desheng Han, Hongbo Zhang, Yuzhang Ma, Zejun Hu, Jianjun Liu, Yong Wang, Xiangyu Wang   +12 more
openaire   +1 more source

Effect of polar cap patches on the polar thermosphere

Journal of Geophysical Research: Space Physics, 1995
Polar cap patches are regions of enhanced ionization that appear when the interplanetary magnetic field is southward. They are created either in the dayside cusp or equatorward of the cusp in the sunlit hemisphere. Once formed, they convect in an antisunward direction across the dark polar cap at speeds of 100 m/s to about 2 km/s.
Ti‐Ze Ma, R. W. Schunk
openaire   +1 more source

Velocity fluctuations associated with polar cap patches

Radio Science, 1996
The digital ionosonde technique has been used to measure the convection in the vicinity of polar cap patches. Two types of velocity fluctuations were seen: (1) parallel fluctuations which are a slowing down and speeding up of the convection without a change in direction, and (2) perpendicular fluctuations which are perpendicular to the average ...
J. W. MacDougall, I. F. Grant, A. Hamza
openaire   +1 more source

Signatures of polar cap patches in ground ionosonde data

Radio Science, 1997
The interpretation of localized density structures in the high‐latitude ionosphere as observed by ground ionosondes is a task that is complicated by the complexity of those structures and by the variety of processes that ionosonde waves undergo. To aid interpretation, we have performed a first‐order analysis of the shapes of traces seen in ionosonde ...
H. G. James, J. W. MacDougall
openaire   +1 more source

Polar cap F layer patches: Structure and dynamics

Journal of Geophysical Research: Space Physics, 1986
Coordinated measurements of F region plasma patches were conducted on February 3/4, 1984, from Thule and Sondrestrom, Greenland. Optical, ionosonde, amplitude scintillation, total electron content (TEC), and incoherent scatter radar measurements were combined to reveal several new aspects of the structure and transport of these localized regions of ...
E. J. Weber, J. A. Klobuchar, J. Buchau, H. C. Carlson, R. C. Livingston, O. de la Beaujardiere, M. McCready, J. G. Moore, G. J. Bishop   +8 more
openaire   +1 more source

Modeling the formation of polar cap patches using large plasma flows

Radio Science, 1996
Recent measurements made with the Sondrestrom incoherent scatter radar have indicated that the formation of polar cap patches can be closely associated with the flow of a large plasma jet. In this paper, we report the results of a numerical study to investigate the role of plasma jets on patch formation, to determine the temporal evolution of the ...
C. E. Valladares, D. T. Decker, R. Sheehan, D. N. Anderson   +3 more
openaire   +1 more source

Occurrence Distribution of Polar Cap Patches: Dependences on UT, Season and Hemisphere

Journal of Geophysical Research: Space Physics, 2021
Keisuke Hosokawa, Yasunobu Ogawa, Yusuke Ebihara   +2 more
exaly  

On the Creation, Depletion, and End of Life of Polar Cap Patches

Journal of Geophysical Research: Space Physics, 2023
Nina Kristine Eriksen, Dag A Lorentzen, Kjellmar Oksavik   +2 more
exaly  

Polar cap patches and the tongue of ionization: A survey of GPS TEC maps from 2009 to 2015

Geophysical Research Letters, 2016
Michael David, A J Coster
exaly  

Substorm onset and expansion phase intensification precursors seen in polar cap patches and arcs

Journal of Geophysical Research: Space Physics, 2013
L R Lyons, Vassilis Angelopoulos, E F Donovan   +2 more
exaly