Now showing items 21-36 of 36

    • Plasma density gradients at the edge of polar ionospheric holes: the absence of phase scintillation 

      Jenner, Luke A.; Wood, Alan G.; Dorrian, Gareth D.; Oksavik, Kjellmar; Yeoman, Timothy; Fogg, Alexandra R.; Coster, Anthea J. (Journal article; Peer reviewed, 2020)
      Polar holes were observed in the high-latitude ionosphere during a series of multi-instrument case studies close to the Northern Hemisphere winter solstice in 2014 and 2015. These holes were observed during geomagnetically ...
    • The science case for the EISCAT_3D radar 

      McCrea, Ian W.; Aikio, Anita; Alfonsi, Lucilla; Belova, Evgenia; Buchert, Stephan C.; Clilverd, Mark; Engler, Norbert; Gustavsson, Björn Johan; Heinselman, C.; Kero, Johan; Kosch, Mike; Lamy, Herve; Leyser, Thomas; Ogawa, Yasunobu; Oksavik, Kjellmar; Pellinen-Wannberg, Asta; Pitout, Frederic; Rapp, Markus; Stanislawska, Iwona; Vierinen, Juha (Peer reviewed; Journal article, 2015-07-29)
      The EISCAT (European Incoherent SCATer) Scientific Association has provided versatile incoherent scatter (IS) radar facilities on the mainland of northern Scandinavia (the EISCAT UHF and VHF radar systems) and on Svalbard ...
    • Scintillation and irregularities from the nightside part of a Sun-aligned polar cap arc 

      van der Meeren, Christer; Oksavik, Kjellmar; Lorentzen, Dag Arne; Paxton, Larry J.; Clausen, Lasse Boy Novock (Peer reviewed; Journal article, 2016-06-18)
      In this paper we study the presence of irregularities and scintillation in relation to the nightside part of a long-lived, Sun-aligned transpolar arc on 15 January 2015. The arc was observed in DMSP UV and particle data ...
    • Scintillation and loss of signal lock from poleward moving auroral forms in the cusp ionosphere 

      Oksavik, Kjellmar; van der Meeren, Christer; Lorentzen, Dag Arne; Baddeley, Lisa; Moen, Jøran Idar (Journal article, 2015-10-27)
      We present two examples from the cusp ionosphere over Svalbard, where poleward moving auroral forms (PMAFs) are causing significant phase scintillation in signals from navigation satellites. The data were obtained using a ...
    • Seasonal and hemispheric asymmetries of F‐region polar cap plasma density: Swarm and CHAMP observations 

      Hatch, Spencer Mark; Haaland, Stein; Laundal, Karl Magnus; Moretto, Therese; Yau, Andrew; Bjoland, Lindis Merete; Reistad, Jone Peter; Ohma, Anders; Oksavik, Kjellmar (Journal article; Peer reviewed, 2020)
      One of the primary mechanisms of loss of Earth's atmosphere is the persistent “cold” ( urn:x-wiley:jgra:media:jgra56068:jgra56068-math-0001 20 eV) ion outflow that has been observed in the magnetospheric lobes over large ...
    • Seasonal and Solar Cycle Variations of Thermally Excited 630.0 nm Emissions in the Polar Ionosphere 

      Kwagala, Norah Kaggwa; Oksavik, Kjellmar; Lorentzen, Dag Arne; Johnsen, Magnar Gullikstad; Laundal, Karl Magnus (Peer reviewed; Journal article, 2018-08)
      Solar cycle and seasonal variations have been found in the occurrence of strong thermally excited 630.0 nm emissions in the polar ionosphere. Measurements from the European Incoherent Scatter Svalbard Radar have been used ...
    • Separation and quantification of ionospheric convection sources: 1. A new technique 

      Reistad, Jone Peter; Laundal, Karl Magnus; Østgaard, Nikolai; Ohma, Anders; Haaland, Stein; Oksavik, Kjellmar; Milan, Stephen Eric (Peer reviewed; Journal article, 2019-07-04)
      This paper describes a novel technique that allows separation and quantification of different sources of convection in the high‐latitude ionosphere. To represent the ionospheric convection electric field, we use the Spherical ...
    • Separation and quantification of ionospheric convection sources: 2. The dipole tilt angle influence on reverse convection cells during northward IMF 

      Reistad, Jone Peter; Laundal, Karl Magnus; Østgaard, Nikolai; Ohma, Anders; Thomas, Evan G.; Haaland, Stein; Oksavik, Kjellmar; Milan, Stephen Eric (Peer reviewed; Journal article, 2019-07-04)
      This paper investigates the influence of Earth's dipole tilt angle on the reverse convection cells (sometimes referred to as lobe cells) in the Northern Hemisphere ionosphere during northward IMF, which we relate to ...
    • Severe and localized GNSS scintillation at the poleward edge of the nightside auroral oval during intense substorm aurora 

      van der Meeren, Christer; Oksavik, Kjellmar; Lorentzen, Dag Arne; Rietveld, Michael T.; Clausen, Lasse Boy Novock (Peer reviewed; Journal article, 2015-12)
      In this paper we study how GPS, GLONASS, and Galileo navigation signals are compromised by strong irregularities causing severe phase scintillation (σϕ>1) in the nightside high-latitude ionosphere during a substorm on 3 ...
    • Simultaneous observations of traveling convection vortices: Ionosphere-thermosphere coupling 

      Kim, Hyomin; Lessard, Marc R.; Jones, Sarah L.; Lynch, Kristina A.; Fernandes, Philip A.; Aruliah, Anasuya L.; Engebretson, Mark J.; Moen, Jøran Idar; Oksavik, Kjellmar; Yahnin, Alexander G.; Yeoman, Timothy K. (Peer reviewed; Journal article, 2017-05)
      We present simultaneous observations of magnetosphere-ionosphere-thermosphere coupling over Svalbard during a traveling convection vortex (TCV) event. Various spaceborne and ground-based instruments made coordinated ...
    • Simultaneous rocket and scintillation observations of plasma irregularities associated with a reversed flow event in the cusp ionosphere 

      Jin, Yaqi; Moen, Jøran Idar; Spicher, Andres; Oksavik, Kjellmar; Miloch, Wojciech Jacek; Clausen, Lasse Boy Novock; Pożoga, Mariusz; Saito, Yoshifumi (Peer reviewed; Journal article, 2019-08-02)
      We present an overview of the ionospheric conditions during the launch of the Investigation of Cusp Irregularities 3 (ICI‐3) sounding rocket. ICI‐3 was launched from Ny‐Ålesund, Svalbard, at 7:21.31 UT on 3 December 2011. ...
    • A space hurricane over the Earth’s polar ionosphere 

      Zhang, Qing-He; Zhang, Yong-Liang; Wang, Chi; Oksavik, Kjellmar; Lyons, Larry R.; Lockwood, Michael; Yang, Hui-Gen; Tang, Bin-Bin; Moen, Jøran Idar; Xing, Zan-Yang; Ma, Yu-Zhang; Wang, Xiang-Yu; Ning, Ya-Fei; Xia, Li-Dong (Journal article; Peer reviewed, 2021)
      In Earth’s low atmosphere, hurricanes are destructive due to their great size, strong spiral winds with shears, and intense rain/precipitation. However, disturbances resembling hurricanes have not been detected in Earth’s ...
    • Space weather challenges of the polar cap ionosphere 

      Moen, Jøran Idar; Oksavik, Kjellmar; Alfonsi, Lucilla; Dåbakk, Yvonne Rinne; Romano, Vineenzo; Spogli, Luca (Peer reviewed; Journal article, 2013)
      This paper presents research on polar cap ionosphere space weather phenomena conducted during the European Cooperation in Science and Technology (COST) action ES0803 from 2008 to 2012. The main part of the work has been ...
    • A statistical study of polar cap flow channels and their IMF by dependence 

      Herlingshaw, Katie; Baddeley, Lisa; Oksavik, Kjellmar; Lorentzen, Dag Arne (Journal article; Peer reviewed, 2020)
      An algorithm to detect high-speed ionospheric flow channels (FCs) in the polar cap was applied to data from the Longyearbyen radar of the Super Dual Auroral Radar Network. The Longyearbyen radar is at high latitude (78.2°N, ...
    • Statistical Study of the Relationship Between Ion Upflow and Field-Aligned Current in the Topside Ionosphere for Both Hemispheres During Geomagnetic Disturbed and Quiet Time 

      Ma, Yu-Zhang; Zhang, Qing-He; Jayachandran, Periyadan T.; Oksavik, Kjellmar; Lyons, Lawrence R.; Xing, Zan-Yang; Zhou, Shan-Yu; Hairston, Marc; Wang, Yong (Journal article; Peer reviewed, 2020)
      A statistical study of ion upflow and field‐aligned currents (FACs) has been performed in the topside ionosphere of both hemispheres for magnetic quiet and disturbed times by using DMSP satellite observations from 2010–2013. ...
    • A Study of Automatically Detected Flow Channels in the Polar Cap Ionosphere 

      Herlingshaw, Katie; Baddeley, Lisa; Oksavik, Kjellmar; Lorentzen, Dag Arne; Bland, Emma (Peer reviewed; Journal article, 2019-11-13)
      This paper presents a new algorithm for detecting high‐speed flow channels in the polar cap. The algorithm was applied to Super Dual Auroral Radar Network data, specifically to data from the new Longyearbyen radar. This ...