Now showing items 1-19 of 19

    • Challenges and Strategic Research Plans for Earth and Heliosphere: Research Infrastructures, Projects and Initiatives 

      Mann, Ingrid; Kauristie, Kirsti; Bamford, Ruth; McCrea, Ian; Moen, Jøran Idar; Oksavik, Kjellmar; Yamauchi, Masanori; Johnsen, Magnar Gullikstad; Turunen, Esa (Cambridge University Press, 2018-07-24)
      We describe existing research infrastructures relevant for space weather and open issues of space weather research including the need for sustainable observation networks and for high-quality data products as basis for ...
      Journal article
    • Dynamic effects of restoring footpoint symmetry on closed magnetic field lines 

      Reistad, Jone Peter; Østgaard, Nikolai; Tenfjord, Paul; Laundal, Karl Magnus; Snekvik, Kristian; Haaland, Stein; Milan, Steve; Oksavik, Kjellmar; Frey, H. U.; Grokott, A. (AGU Publications, 2016-05-05)
      Here we present an event where simultaneous global imaging of the aurora from both hemispheres reveals a large longitudinal shift of the nightside aurora of about 3 h, being the largest relative shift reported on from ...
      Journal article
    • Dynamic properties of throat aurora revealed by simultaneous ground and satellite observations 

      Chen, Xiangcai; Han, Desheng; Lorentzen, Dag Arne; Oksavik, Kjellmar; Moen, Jøran Idar; Baddeley, Lisa (American Geophysical Union, 2017-03)
      Throat aurora is defined as south-north aligned auroral arcs equatorward of the dayside cusp aurora and was suggested to be the results of cold magnetospheric plasma interaction with magnetopause reconnection, but its ...
      Journal article
    • GPS scintillation and irregularities at the front of an ionization tongue in the nightside polar ionosphere 

      van der Meeren, Christer; Oksavik, Kjellmar; Lorentzen, Dag Arne; Moen, Jøran Idar; Romano, Vincenzo (WileyAmerican Geophysical Union, 2014-10)
      In this paper we study a tongue of ionization (TOI) on 31 October 2011 which stretched across the polar cap from the Canadian dayside sector to Svalbard in the nightside ionosphere. The TOI front arrived over Svalbard ...
      Journal article
    • GPS Scintillations and Losses of Signal Lock at High Latitudes During the 2015 St. Patrick's Day Storm 

      Jin, Yaqi; Oksavik, Kjellmar (Wiley, 2018-09)
      We investigate the Global Positioning System (GPS) amplitude and phase scintillations during a severe geomagnetic storm on 17 March 2015. The auroral oval expanded significantly due to a strongly southward interplanetary ...
      Journal article
    • GPS scintillations associated with cusp dynamics and polar cap patches 

      Jin, Yaqi; Moen, Jøran Idar; Oksavik, Kjellmar; Spicher, Andres; Clausen, Lasse Boy Novock; Miloch, Wojciech Jacek (EDP Sciences, 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 ...
      Journal article
    • How Often Do Thermally Excited 630.0 nm Emissions Occur in the Polar Ionosphere? 

      Kwagala, Norah Kaggwa; Oksavik, Kjellmar; Lorentzen, Dag Arne; Johnsen, Magnar Gullikstad (American Geophysical Union, 2018-01)
      This paper studies thermally excited emissions in the polar ionosphere derived from European Incoherent Scatter Svalbard radar measurements from the years 2000–2015. The peak occurrence is found around magnetic noon, where ...
      Journal article
    • In-flight calibration of NOAA POES proton detectors - Derivation of the MEPED correction factors 

      Sandanger, Marit Irene; Ødegaard, Linn-Kristine Glesnes; Tyssøy, Hilde Nesse; Stadsnes, Johan; Søraas, Finn; Oksavik, Kjellmar; Aarsnes, Kjell (Wiley, 2015-11-25)
      The MEPED instruments on board the NOAA POES and MetOp satellites have been continuously measuring energetic particles in the magnetosphere since 1978. However, degradation of the proton detectors over time leads to an ...
      Journal article
    • Intensity asymmetries in the dusk sector of the poleward auroral oval due to IMF Bx 

      Reistad, Jone Peter; Østgaard, Nikolai; Laundal, Karl Magnus; Haaland, Stein; Tenfjord, Paul; Snekvik, Kristian; Oksavik, Kjellmar; Milan, Steve (WileyAmerican Geophysical Union, 2014-12)
      In the exploration of global-scale features of the Earth's aurora, little attention has been given to the radial component of the Interplanetary Magnetic Field (IMF). This study investigates the global auroral response in ...
      Journal article
    • Observations of asymmetries in ionospheric return flow during different levels of geomagnetic activity 

      Reistad, Jone Peter; Østgaard, Nikolai; Laundal, Karl Magnus; Ohma, Anders; Snekvik, Kristian; Tenfjord, Paul; Grocott, Adrian; Oksavik, Kjellmar; Milan, Steve; Haaland, Stein (Wiley, 2018-06)
      It is known that the magnetic field of the Earth's closed magnetosphere can be highly displaced from the quiet‐day configuration when interacting with the interplanetary magnetic field (IMF), an asymmetry largely controlled ...
      Journal article
    • On the contribution of thermal excitation to the total 630.0 nm emissions in the northern cusp ionosphere 

      Kwagala, Norah Kaggwa; Oksavik, Kjellmar; Lorentzen, Dag Arne; Johnsen, Magnar Gullikstad (American Geophysical Union, 2017-01)
      Direct impact excitation by precipitating electrons is believed to be the main source of 630.0 nm emissions in the cusp ionosphere. However, this paper investigates a different source, 630.0 emissions caused by thermally ...
      Journal article
    • 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 (Springer, 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 ...
      Journal article
    • 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 (American Geophysical Union, 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 ...
      Journal article
    • 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 (Wiley, 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 ...
      Journal article
    • 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 (American Geophysical Union, 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 ...
      Journal article
    • 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 (American Geophysical Union, 2018-08-28)
      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 ...
      Journal article
    • 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 (American Geophysical Union, 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 ...
      Journal article
    • 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. (American Geophysical Union, 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 ...
      Journal article
    • Space weather challenges of the polar cap ionosphere 

      Moen, Jøran Idar; Oksavik, Kjellmar; Alfonsi, Lucilla; Dåbakk, Yvonne Rinne; Romano, Vineenzo; Spogli, Luca (EDP Sciences, 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 ...
      Journal article