Results 21 to 30 of about 742,768 (286)

Polar cap arcs from the magnetosphere to the ionosphere: kinetic modelling and observations by Cluster and TIMED [PDF]

Annales Geophysicae, 2012
On 1 April 2004 the GUVI imager onboard the TIMED spacecraft spots an isolated and elongated polar cap arc. About 20 min later, the Cluster satellites detect an isolated upflowing ion beam above the polar cap.
R. Maggiolo, M. Echim, M. Echim, C. Simon Wedlund, Y. Zhang, D. Fontaine, G. Lointier, J.-G. Trotignon   +7 more
doaj   +1 more source

Mesoscale observations of Joule heating near an auroral arc and ion-neutral collision frequency in the polar cap E region [PDF]

, 2011
We report on the first mesoscale combined ionospheric and thermospheric observations, partly in the vicinity of an auroral arc, from Svalbard in the polar cap on 2 February 2010. The EISCAT Svalbard radar employed a novel scanning mode in order to obtain
Wild, J.A., Yiu, I., Kosch, M.J., Anderson, C., I. Yiu, Y. Ogawa, Aruliah, A., Tsuda, T., I. W. McCrea, L. J. Baddeley, S. Nozawa, Howells, V., A. Aruliah, J. A. Wild, McCrea, I.W., V. Howells, Ogawa, Y., Nozawa, S., M. J. Kosch, C. Anderson, Baddeley, L.J., T. Tsuda   +21 more
core   +5 more sources

Combined ESR and EISCAT observations of the dayside polar cap and auroral oval during the May 15, 1997 storm [PDF]

Annales Geophysicae, 2000
The high-latitude ionospheric response to a major magnetic storm on May 15, 1997 is studied and different responses in the polar cap and the auroral oval are highlighted.
H. Liu, H. Liu, H. Liu, H. Liu, K. Schlegel, S.-Y. Ma, S.-Y. Ma   +6 more
doaj   +1 more source

Aurora and open magnetic flux during isolated substorms, sawteeth, and SMC events [PDF]

Annales Geophysicae, 2007
Using Polar UVI LBHl and IMAGE FUV WIC data, we have compared the auroral signatures and polar cap open flux for isolated substorms, sawteeth oscillations, and steady magnetospheric convection (SMC) events.
A. D. DeJong, X. Cai, R. C. Clauer, J. F. Spann   +3 more
doaj   +1 more source

Method to locate the polar cap boundary in the nightside ionosphere and application to a substorm event [PDF]

, 2006
International audienceIn this paper we describe a new method to be used for the polar cap boundary (PCB) determination in the nightside ionosphere by using the EISCAT Svalbard radar (ESR) field-aligned measurements by the 42-m antenna and southward ...
A. T. Aikio, O. Amm, Amm, Olaf, Aikio, A.T., Aikio, Anita T., Aikio, A. T., A. Kozlovsky, Kozlovsky, Alexander, Pitkänen, Timo, Pitkänen, T., Amm, O., Kozlovsky, A., T. Pitkänen   +12 more
core   +2 more sources

On a new process for cusp irregularity production [PDF]

Annales Geophysicae, 2008
Two plasma instability mechanisms were thought until 2007 to dominate the formation of plasma irregularities in the F region high latitude and polar ionosphere; the gradient-drift driven instability, and the velocity-shear driven instability.
H. C. Carlson, H. C. Carlson, K. Oksavik, J. Moen   +3 more
doaj   +1 more source

On solar protons and polar cap absorption: Constraints on an empirical relationship [PDF]

, 2004
International audienceA large database of Solar Proton Events (SPE) from the period 1995 to 2001 is used to investigate the relationship between proton flux at geostationary orbit and Cosmic Noise Absorption (CNA) in the auroral zone. The effect of solar
A. Senior, Senior, A., S. R. Marple, Kavanagh, A. J., A. J. Kavanagh, Marple, S. R., McCrea, I. W., F. Honary, I. W. McCrea, Honary, F.   +9 more
core   +2 more sources

GPS scintillations associated with cusp dynamics and polar cap patches

Journal of Space Weather and Space Climate, 2017
This paper investigates the relative scintillation level associated with cusp dynamics (including precipitation, flow shears, etc.) with and without the formation of polar cap patches around the cusp inflow region by the EISCAT Svalbard radar (ESR) and ...
Jin Yaqi, Moen Jøran I., Oksavik Kjellmar, Spicher Andres, Clausen Lasse B.N., Miloch Wojciech J.   +5 more
doaj   +1 more source

GPS scintillation effects associated with polar cap patches and substorm auroral activity: direct comparison

Journal of Space Weather and Space Climate, 2014
We directly compare the relative GPS scintillation levels associated with regions of enhanced plasma irregularities called auroral arcs, polar cap patches, and auroral blobs that frequently occur in the polar ionosphere.
Jin Yaqi, Moen Jøran I., Miloch Wojciech J.   +2 more
doaj   +1 more source

The location of the open-closed magnetic field line boundary in the dawn sector auroral ionosphere [PDF]

Annales Geophysicae, 2004
As a measure of the degree of coupling between the solar wind-magnetosphere-ionosphere systems, the rate at which the size of the polar cap (the region corresponding to ionospheric termini of open magnetic flux tubes) varies is of prime importance ...
J. A. Wild, S. E. Milan, C. J. Owen, J. M. Bosqued, M. Lester, D. M. Wright, H. Frey, C. W. Carlson, A. N. Fazakerley, H. Rème   +9 more
doaj   +1 more source