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Nikolai Østgaard

Professor, Leader of Birkeland Centre for Space Science
  • E-mailNikolai.Ostgaard@uib.no
  • Phone+47 55 58 27 94+47 472 70 653
  • Visitor Address
    Allegt 55
    5007 Bergen
    Room 
    446
  • Postal Address
    Postboks 7803
    5020 BERGEN
Academic lecture
  • Ohma, Anders; Østgaard, Nikolai; Reistad, Jone Peter; Tenfjord, Paul; Laundal, Karl Magnus; Moretto, Therese; Haaland, Stein; Krcelic, Patrik; Milan, Stephen Eric. 2019. Observations of Asymmetric Lobe Convection for Weak and Strong Tail Reconnection.
  • Ohma, Anders; Østgaard, Nikolai; Reistad, Jone Peter; Tenfjord, Paul; Laundal, Karl Magnus. 2019. How asymmetries in Geospace evolve during increased tail reconnection.
  • Ohma, Anders; Østgaard, Nikolai; Reistad, Jone Peter; Tenfjord, Paul; Laundal, Karl Magnus. 2019. How Asymmetries in Geospace Evolve During Substorms.
  • Ohma, Anders; Østgaard, Nikolai; Reistad, Jone Peter; Tenfjord, Paul; Laundal, Karl Magnus; Moretto, Therese; Haaland, Stein; Krcelic, Patrik; Milan, S. E. 2019. Cluster EDI Observations of the Asymmetric Plasma Convection in the Magnetotail Lobes During Different Levels of Tail Reconnection Rate .
  • Reistad, Jone Peter; Laundal, Karl Magnus; Ohma, Anders; Østgaard, Nikolai; Thomas, Evan G.; Haaland, Stein; Oksavik, Kjellmar; Milan, Stephen Eric. 2019. A new way to identify and quantify the sources of ionospheric convection.
  • Reistad, Jone Peter; Laundal, Karl Magnus; Østgaard, Nikolai; Ohma, Anders; Snekvik, Kristian; Tenfjord, Paul. 2018. Plasma circulation inside the polar cap and lobe reconnection.
  • Hesse, Michael; Kuznetsova, M; Liu, Yi-Hsin; Rastatter, Lutz; Østgaard, Nikolai; Birn, Joachim. 2017. The roles of IMF By, dipole tilt, and conductance differences in establishing nonconjugate auroral features.
  • Reistad, Jone Peter; Østgaard, Nikolai; Laundal, Karl Magnus; Tenfjord, Paul; Snekvik, Kristian; Haaland, Stein; Milan, Stephen Eric; Ohma, Anders; Grocott, Adrian; Oksavik, Kjellmar. 2017. The influence of plasma flows bringing the magnetotail back to a more symmetric configuration.
  • Laundal, Karl Magnus; Reistad, Jone Peter; Tenfjord, Paul; Snekvik, Kristian; Østgaard, Nikolai; Ohma, Anders. 2017. Seasonal and IMF-controlled variations in the large-scale true horizontal ionospheric current.
  • Laundal, Karl Magnus; Østgaard, Nikolai. 2017. Norwegian contributions to the ISWI program.
  • Østgaard, Nikolai. 2017. Norwegian contributions to SCOSTEP/VarSITI.
  • Laundal, Karl Magnus; Finlay, Christopher C.; Olsen, NIls; Reistad, Jone Peter; Tenfjord, Paul; Østgaard, Nikolai; Ohma, Anders; Snekvik, Kristian; Haaland, Stein; Milan, Stephen Eric. 2017. North-south asymmetries in polar ionospheric currents - effects of asymmetries in the main magnetic field.
  • Haaland, Stein; Laundal, Karl Magnus; Lybekk, Bjørn; Baddeley, Lisa; Bjoland, Lindis Merete; Pedersen, Arne; Tenfjord, Paul; Østgaard, Nikolai; Gustavsson, Björn Johan; Reistad, Jone Peter; Snekvik, Kristian; Ohma, Anders. 2017. North-south asymmetries in lobe density: Cluster observations.
  • Haaland, Stein; Lybekk, Bjørn; Maes, Lukas; Laundal, Karl Magnus; Baddeley, Lisa; Bjoland, Lindis Merete; Pedersen, Arne; Tenfjord, Paul; Østgaard, Nikolai; Gustavsson, Björn Johan; Reistad, Jone Peter; Snekvik, Kristian; Ohma, Anders. 2017. North-South asymmetries in cold plasma density.
  • Haaland, Stein; Baddeley, Lisa; Olafsson, Kjartan; Østgaard, Nikolai; Partamies, Noora; Tanskanen, Eija I.; Vaivads, Andris. 2017. Looking South for the Northern Lights:Substorm Physics as University Curriculum.
  • Tenfjord, Paul; Haaland, Stein; Laundal, Karl Magnus; Milan, Steve; Reistad, Jone Peter; Snekvik, Kristian; Østgaard, Nikolai. 2017. How the IMF By induces a By-component on closed field lines during northward IMF Bz.
  • Hesse, Michael; Friis-Christensen, Eigil; Moretto, T; Kuznetsova, M; Østgaard, Nikolai; Tenfjord, Paul; Opgenoorth, H. 2017. Does the Magnetosphere go to Sleep?
  • Snekvik, Kristian; Østgaard, Nikolai; Tenfjord, Paul; Reistad, Jone Peter; Laundal, Karl Magnus; Milan, Stephen Eric; Haaland, Stein. 2017. Dayside and nightside magnetic field responses at 780 km altitude to dayside reconnection.
  • Østgaard, Nikolai. 2017. Conjugate auroral imaging: How asymmetric can geospace be ? Magnetic storm 17 aug 2001.
  • Laundal, Karl Magnus; Finlay, Christopher C.; Olsen, NIls; Reistad, Jone Peter; Tenfjord, Paul; Østgaard, Nikolai; Ohma, Anders; Snekvik, Kristian; Haaland, Stein; Milan, Stephen Eric. 2017. Characterizing external influence on the large-scale polar ionospheric current system.
  • Østgaard, Nikolai; Marisaldi, Martino; Albrechtsen, Kjetil; Kochkin, Pavlo; Lehtinen, Nikolai; Mezentsev, Andrey; Skeltved, Alexander Broberg. 2017. A Synergic Approach to the Study of TGFs and Energetic Radiation from Thunderstorms.
  • Gjesteland, Thomas; Østgaard, Nikolai; Marisaldi, Martino; Briggs, M. S.; Smith, David M. 2016. Stereo Observations of Terrestrial Gamma-ray Flashes.
  • Mezentsev, Andrew; Østgaard, Nikolai; Gjesteland, Thomas; Skeltved, Alexander Broberg; Cummer, Steven A. 2015. VLF sferics associated with TGFs.
  • Østgaard, Nikolai; Gjesteland, Thomas; Christian, Hugh; Albrechtsen, Kjetil; Carlson, Brant Edward; Collier, Andrew B.; Cummer, Steven; Lu, Gaopeng. 2015. The sequence of events in a lightning stroke: terrestrial gamma ray flash, radio signal and optical lightning.
  • Laundal, Karl Magnus; Olsen, N; Finlay, C; Østgaard, Nikolai; Tenfjord, Paul; Reistad, Jone Peter; Snekvik, Kristian. 2015. Statistical maps of Birkeland currents from Swarm magnetometer measurements.
  • Østgaard, Nikolai; Gjesteland, Thomas; Carlson, Brant Edward; Collier, Andrew B.; Cummer, Steven A.; Lu, Gaopeng; christian, hugh. 2015. Simultaneous observations of optical lightning and terrestrial gamma flash from space and radio signals on ground.
  • Østgaard, Nikolai; Gjesteland, Thomas; Carlson, Brant Edward; Collier, Andrew B.; Cummer, Steven A.; Lu, Gang; Christian, Hugh J. 2015. Simultaneous observations of optical lightning and terrestrial gamma flash and radio signals on ground.
  • Aamodt, Vegard; Østgaard, Nikolai; Gjesteland, Thomas; Carlson, Brant Edward; Collier, Andrew B. 2015. Search for Terrestrial Electron Beams (TEBs) in SAMPEX data.
  • Tenfjord, Paul; Østgaard, Nikolai; Haaland, Stein; Laundal, Karl Magnus; Milan, Steve; Reistad, Jone Peter; Snekvik, Kristian. 2015. On which timescales are By induced in the closed magnetosphere?
  • Skeltved, Alexander Broberg; Østgaard, Nikolai; Gjesteland, Thomas; Carlson, Brant Edward. 2015. Modeling the production and acceleration of runaway electrons in strong inhomogeneous electric fields with GEANT4.
  • Snekvik, Kristian; Laundal, Karl Magnus; Østgaard, Nikolai; Tenfjord, Paul; Reistad, Jone Peter; Milan, Steve; Haaland, Stein. 2015. Magnetic field patterns near the polar cap boundary.
  • Østgaard, Nikolai. 2015. How is Earth coupled to space?
  • Tenfjord, Paul; Snekvik, Kristian; Østgaard, Nikolai; Laundal, Karl Magnus; Reistad, Jone Peter; Milan, Steve; Haaland, Stein. 2015. Generation of Birkeland Currents during IMF By; Mechanisms and theory.
  • Laundal, Karl Magnus; Förster, Matthias; Haaland, Stein; Snekvik, Kristian; Østgaard, Nikolai; Reistad, Jone Peter; Tenfjord, Paul; Milan, Steve. 2015. Effects of electric field component representation on estimated cross polar cap potential - Implications for interhemispheric asymmetries.
  • Laundal, Karl Magnus; Förster, Matthias; Snekvik, Kristian; Østgaard, Nikolai; Reistad, Jone Peter; Tenfjord, Paul; Milan, Steve. 2015. Effects of electric field component representation on estimated cross polar cap potential - Implications for interhemispheric asymmetries.
  • Lehtinen, Nikolai; Østgaard, Nikolai. 2015. Dimension of a fractal streamer structure.
  • Rexer, Theresa; Østgaard, Nikolai; Reistad, Jone Peter; Laundal, Karl Magnus. 2015. Current systems associated with Non-Conjugate Aurora.
  • Reistad, Jone Peter; Østgaard, Nikolai; Tenfjord, Paul; Snekvik, Kristian; Laundal, Karl Magnus; Milan, Steve; Oksavik, Kjellmar. 2015. Are there auroral signatures related to asymmetric generation of field-aligned currents in the tail due to an IMF By induced twist?
  • Gjesteland, Thomas; Christian, Hugh; Østgaard, Nikolai. 2015. An observation of a TGF from the convective core of a thundercloud.
  • Gjesteland, Thomas; Østgaard, Nikolai; Nisi, Ragnhild Schrøder; Collier, Andrew B.; Smith, David M.; Cummer, Steven A.; Lu, Gaopeng. 2014. Twelve Years of RHESSI TGFs - The second RHESSI TGF catalog.
  • Infanger, Andrew; Smith, David M.; Gjesteland, Thomas; Østgaard, Nikolai. 2014. Toward an optimized Third Catalog of RHESSI TGFs.
  • Østgaard, Nikolai. 2014. TGF observations.
  • Østgaard, Nikolai; Carlson, Brant Edward; Grøndahl, Øystein; Nisi, Ragnhild Schrøder; Gjesteland, Thomas. 2014. Search for X-rays and relativistic electrons in laboratory discharge experiments.
  • Aamodt, Vegard; Østgaard, Nikolai; Gjesteland, Thomas; Carlson, Brant Edward; Collier, Andrew B. 2014. Search for Terrestrial Electron Beams (TEB) in SAMPEX data.
  • Kelley, N. A.; Smith, David M.; Bowers, G. S.; Buzbee, P; Dwyer, J. R.; Cramer, E. S.; Rassoul, H.J.; Cummer, Steven A.; Gjesteland, Thomas; Østgaard, Nikolai. 2014. Recent Results from ADELE and RHESSI.
  • Lehtinen, Nikolai; Inan, Umran S.; Østgaard, Nikolai. 2014. On the spatial scale of streamers.
  • Lehtinen, Nikolai; Inan, Umran S.; Østgaard, Nikolai. 2014. On the Spatial Scale of Streamers.
  • Skeltved, Alexander Broberg; Østgaard, Nikolai; Gjesteland, Thomas; Collier, Andrew B. 2014. Modelling the runaway electron avalanche and the feedback mechanism with GEANT4.
  • Montanya, J.; Fabro, F; van der Velde, O; Aranguren, David; Williams, E.; Morales, C; Betz, H. D.; Gjesteland, Thomas; Østgaard, Nikolai; Soula, S.; Pineda, N. A.; Smith, David M. 2014. Lightning activity and radar for a TGF case in Colombia.
  • Reistad, Jone Peter; Østgaard, Nikolai; Laundal, Karl Magnus; Snekvik, Kristian; Tenfjord, Paul; Oksavik, Kjellmar. 2014. Hemispheric differences in solar wind – magnetosphere interactions.
  • Østgaard, Nikolai; Gjesteland, Thomas; Carlson, Brant Edward; Collier, Andrew B.; Cummer, Steven A.; Lu, Gaopeng; Christian, H.J. 2014. First simultaneous observations of optical lightning and terrestrial gamma flash from space.
  • Lehtinen, Nikolai; Østgaard, Nikolai; Inan, Umran S. 2014. Dynamics of a streamer structure.
  • Reistad, Jone Peter; Østgaard, Nikolai; Laundal, Karl Magnus; Oksavik, Kjellmar. 2014. Conjugate and non-conjugate aspects of the aurora.
  • Reistad, Jone Peter; Østgaard, Nikolai; Laundal, Karl Magnus; Haaland, Stein; Tenfjord, Paul; Oksavik, Kjellmar. 2014. Comparison of solar wind driving of the aurora in the two hemispheres due to the solar wind dynamo.
  • Reistad, Jone Peter; Østgaard, Nikolai; Laundal, Karl Magnus; Haaland, S.; Tenfjord, Paul; Oksavik, Kjellmar. 2014. Comparison of solar wind driving of the aurora in the two hemispheres due to solar wind dynamo.
  • Østgaard, Nikolai. 2014. Birkeland Centre for Space Science.
  • Reistad, Jone Peter; Østgaard, Nikolai; Laundal, Karl Magnus; Haaland, Stein; Tenfjord, Paul; Snekvik, Kristian; Oksavik, Kjellmar; Milan, Steve. 2014. Asymmetric Solar Wind dynamo efficiency and IMF Bx.
  • Nisi, Ragnhild Schrøder; Østgaard, Nikolai; Gjesteland, Thomas. 2014. An altitude and distance correction to the initial fluence distribution of TGF.
  • Skeltved, Alexander Broberg; Østgaard, Nikolai; Carlson, Brant Edward; Gjesteland, Thomas. 2014. A study of the runaway relativistic electron avalanche and the feedback theory using GEANT4.
  • Østgaard, Nikolai; Reistad, Jone Peter; Tenfjord, Paul; Laundal, Karl Magnus. 2013. What are the mechanisms that produce auroral asymmetries in the conjugate hemispheres?
  • Gjesteland, Thomas; Østgaard, Nikolai; Marisaldi, Martino; fuschino, f; arnona, e; laviola, s. 2013. Unusual bright TGF from low cloud tops over the Mediterranean sea.
  • Østgaard, Nikolai. 2013. UV and X-ray imaging of aurora and other atmospheric phenomena.
  • Østgaard, Nikolai. 2013. Terrestrial gamma ray flashes, the most energetic photon phenomenon in our atmosphere.
  • Østgaard, Nikolai. 2013. Terrestrial gamma ray flashes, the most energetic photon phenomenon in our atmosphere.
  • Østgaard, Nikolai. 2013. Terrestrial Gamma-ray Flashes - the most energetic photon phenomenon in our atmosphere.
  • Østgaard, Nikolai. 2013. Terrestrial Gamma-ray Flashes - the most energetic photon phenomenon in our atmosphere.
  • Gjesteland, Thomas; Østgaard, Nikolai; Collier, Andrew B.; Martino, Marisaldi; Fabio, Fushino; Arnona, Enrico; Laviola, Sante. 2013. Terrestrial Gamma ray Flashes observed over low clod tops.
  • Gjesteland, Thomas; Østgaard, Nikolai; Marisaldi, Martino; Fabio, Fushino; Sante, Laviola; Collier, Andrew B. 2013. Terrestrial Gamma ray Flashes observed over low clod tops.
  • Carlson, Brant Edward; Scherre, Z; Webere, K; LeCaptain, K; Østgaard, Nikolai; Grøndahl, Øystein; Kochkin, P. 2013. Spatial Correlations and Distributions in Energetic Electron Production by Meter­Scale Sparks.
  • Reistad, Jone Peter; Østgaard, Nikolai; Laundal, Karl Magnus; Oksavik, Kjellmar. 2013. Simultaneous global imaging as a tracer of true conjugate regions.
  • Østgaard, Nikolai. 2013. Scientific Programme of Birkeland Centre in Space Physics.
  • Smith, David M.; Buzbee, P; Infanger, A; Cummer, Steven A.; Dwyer, J. R.; Lu, Gaopeng; Gjesteland, Thomas; Østgaard, Nikolai. 2013. Results from the third RHESSI catalog of Terrestrial Gamma-ray Flashes.
  • Kelley, N. A.; Smith, David M.; Bowers, G. S.; Dwyer, J. R.; Cummer, Steven A.; Gjesteland, Thomas; Østgaard, Nikolai; Lu, Gaopeng; Infanger, A; Buzbee, P. 2013. Recent Results from ADELE and RHESSI.
  • Østgaard, Nikolai. 2013. Nye fenomener i romforskning - gammaglimt, blå jetter og røde ånder.
  • Laundal, Karl Magnus; Østgaard, Nikolai; Reistad, Jone Peter; Oksavik, Kjellmar. 2013. Non-Conjugate Features in the Auroral Ovals in the two Hemispheres.
  • Reistad, Jone Peter; Haaland, Stein; Østgaard, Nikolai; Laundal, Karl Magnus; Tenfjord, Paul; Oksavik, Kjellmar. 2013. Investigation of the role of IMF Bx on magnetopause characteristic past the terminator.
  • Reistad, Jone Peter; Haaland, Stein; Østgaard, Nikolai; Laundal, Karl Magnus; Tenfjord, Paul Arne Riksheim; Oksavik, Kjellmar. 2013. Investigation of a possible IMF Bx influence on magnetopause characteristics.
  • Reistad, Jone Peter; Haaland, Stein; Østgaard, Nikolai; Laundal, Karl Magnus; Tenfjord, Paul; Oksavik, Kjellmar. 2013. Investigation of a possible IMF Bx influence on magnetopause characteristic.
  • Tenfjord, Paul; Østgaard, Nikolai; Haaland, Stein; Reistad, Jone Peter; Laundal, Karl Magnus. 2013. Inter-hemispheric currents in the ring current region.
  • Collier, Andrew B.; Gjesteland, Thomas; Østgaard, Nikolai. 2013. Intensity of Lightning Associated with TGFs.
  • Reistad, Jone Peter; Østgaard, Nikolai; Laundal, Karl Magnus; Tenfjord, Paul; Oksavik, Kjellmar; Haaland, Stein. 2013. Intensity asymmetries between the northern and southern auroral ovals associated with the x-component of the Interplanetary Magnetic Field.
  • Østgaard, Nikolai; Gjesteland, Thomas; Carlson, Brant Edward; Collier, Andrew B.; Cummer, Steven A.; Lu, Gaopeng; Christian, Hugh. 2013. First simultaneous observations of optical lightning and terrestrial gamma flash from space.
  • Liemohn, Mike; Østgaard, Nikolai; Reistad, Jone Peter; ganiuskina, s; Daglis, I. 2013. Defining and Resolving Current Systems in Geospace.
  • Skeltved, Alexander Broberg; Østgaard, Nikolai; Carlson, Brant Edward; Gjesteland, Thomas. 2013. A study of the relativistiv runaway electron avalanche and the feedback theories to explain terrestrial gammaray production.
  • Østgaard, Nikolai; Carlson, Brant Edward; Hansen, Ragnhild Schrøder; Gjesteland, Thomas; Collier, Andrew B. 2011. The true distribution of TGF fluence measured from space.
  • Østgaard, Nikolai. 2011. The global auroral response to solar wind - Earth magnetosphere coupling.
  • Carlson, Brant Edward; Gjesteland, Thomas; Østgaard, Nikolai. 2011. The frequency of terrestrial gamma-ray flash electron beam observations.
  • Carlson, Brant Edward; Gjesteland, Thomas; Østgaard, Nikolai. 2011. The TGF source luminosity distribution.
  • Collier, Andrew B.; Gjesteland, Thomas; Østgaard, Nikolai. 2011. Terrestrial Gamma-ray Flash Intensity Distribution.
  • Collier, Andrew B.; Gjesteland, Thomas; Østgaard, Nikolai. 2011. Terrestrial Gamma-Ray Flash Intensity Distribution.
  • Vaktdal, Siri M.; Østgaard, Nikolai; Gjesteland, Thomas; Hansen, Ragnhild Schrøder; Collier, Andrew B.; Carlson, Brant Edward. 2011. TGF dependence on magnetic latitude and solar zenith angle.
  • Juusola, Liisa; Østgaard, Nikolai; Tanskanen, Eija Irene. 2011. Statistics of Plasma Sheet Convection.
  • Khotyaintsev, Y.; Retino, A; Vaivads, Andris; Kontar, E; Reid, H; Gosling, J; Vlahos, L; Fujimoto, M; Krucker, S; Bale, S. D.; Neukirch, T; Semenov, V. S.; Østgaard, Nikolai. 2011. Particle Acceleration During Solar Flares and Magnetospheric Substorms.
  • Østgaard, Nikolai; Hansen, Ragnhild Schrøder; Gjesteland, Thomas; Carlson, Brant Edward; Collier, Andrew B. 2011. Occurence frequency and fluence of TGFs.
  • Østgaard, Nikolai; Hansen, Ragnhild Schrøder; Gjesteland, Thomas; Carlson, Brant Edward; Collier, Andrew B. 2011. Occurence frequency and fluence of TGFs.
  • Carlson, Brant Edward; Fishman, G; Briggs, M. S.; Cohen, M. B.; Østgaard, Nikolai; Said, R. K.; Gjesteland, Thomas; Connaughton, V. 2011. Modeling TGF electron beams and constraints on the TGF source.
  • Renard, J-B; Pincon, J.; Østgaard, Nikolai; Berthet, G; Brun-Huret, N. 2011. Imapct of recent results About TGFs and TLEs to the scientific return OF the cobrat project.
  • Snekvik, Kristian; Tanskanen, Eija Irene; Østgaard, Nikolai. 2011. Flux cloaure during magnetotail reconnection.
  • Håland, Stein Egil; Søraas, Finn; Daly, P.; Johnsen, Christine; Georgescu, E.; Kronberg, E.; Oksavik, Kjellmar; Østgaard, Nikolai. 2011. Determination of polar cap size and shape using energetic particles.
  • Gjesteland, Thomas; Østgaard, Nikolai; Collier, Andrew B. 2011. Constrains on the Terrestrial Gamma-ray Flashes Emission Cone by Spectral Analysis of Geolocated Events. EGU.
  • Gjesteland, Thomas; Østgaard, Nikolai; Collier, Andrew B.; Carlson, Brant Edward; Cohen, Morris B.; Lehtinen, Nikolai. 2011. Confining the angular distribution of TGF emission.
  • Østgaard, Nikolai; Humberset, Beate Krøvel; Laundal, Karl Magnus; Frey, H. U.; Sigwarth, J. B.; Aasnes, A.; Weygand, J. 2011. Auroral asymmetries in the conjugate hemispheres during substorm onset and expansion phase.
  • Østgaard, Nikolai; Laundal, Karl Magnus; Stadsnes, Johan. 2011. Auroral asymmetries in the conjugate hemispheres.
  • Østgaard, Nikolai. 2011. Auroral asymmetries in the conjugate hemispheres.
  • Østgaard, Nikolai. 2011. Auroral asymmetries in the conjugate hemispheres.
  • Østgaard, Nikolai; Humberset, Beate Krøvel; Juusola, Liisa; Laundal, Karl Magnus; Haaland, Stein; Aasnes, A.; Weygand, J. 2011. Asymmetries of substorm onset location and the dynamic behavior of auroral substorms during expansion phase.
  • Gjesteland, Thomas; Østgaard, Nikolai; Collier, Andrew B.; Carlson, Brant Edward; Hansen, Ragnhild Schrøder; Eyles, C; Stopnitzky, E; Smith, D. 2011. Are there more TGFs in the RHESSI data.
  • Neubert, T; Reglero, V; Østgaard, Nikolai; blanc, elisabeth. 2009. The ASIM Mission for Studies of Severe Thunderstorms,.
  • Østgaard, Nikolai; Humberset, Beate Krøvel; Laundal, Karl Magnus; Frey, H.U.; Sigwarth, J.B.; Åsnes, Arne; Weygand, James M. 2009. Substorm auroral asymmetries in the conjugate hemispheres during onset and expansion phase.
  • Snekvik, Kristian; Juusola, Liisa; Amm, Olaf; Østgaard, Nikolai. 2009. Reconnection Hall current system observed in the magnetotail and in the ionosphere.
  • Østgaard, Nikolai; Gjesteland, Thomas; Connell, Paul H.; Stadsnes, Johan. 2009. Production altitude, initial distributions and time delays for TGFs when instrumental deadtime effects are treated properly.
  • Laundal, Karl Magnus; Østgaard, Nikolai. 2009. IPY-ICESTAR Arctic Frontiers.
  • Laundal, Karl Magnus; Østgaard, Nikolai. 2009. IMF Bx Effects on Interhemispheric Polar Cap Asymmetries Inferred From Conjugate Auroral Imaging.
  • Liemohn, Mike; Brandt, Pontus; Denton, Mike; Donovan, Eric; Lester, Mark; Liu, William; Milan, Steve; Østgaard, Nikolai; Palmroth, Minna; Uritsky, Vadim; Zhang, X. 2009. Go With the Flow: The Reductionist View of Geospace at the System Level.
  • Laundal, Karl Magnus; Østgaard, Nikolai. 2009. Conjugate aurora observations of substorms IAGA meeting.
  • Frey, H.U.; Chaston, C; Fu, S; Haerendel, G.; Juusola, Liisa; Karlsson, T; Lanchester, Betty; Nakamura, Rumi; Østgaard, Nikolai; Sakanoi, T; Seran, E; Whiterand, D. 2009. Auroral Small-and Meso-Scale Structures, Origin and Function.
  • Laundal, Karl Magnus; Østgaard, Nikolai. 2009. Asymmetric aurora detected in the two hemispheres simultaneously.
  • Østgaard, Nikolai; Laundal, Karl Magnus. 2009. Asymmetric aurora detected in the two hemispheres simultaneously.
  • Østgaard, Nikolai; Laundal, Karl Magnus. 2009. Asymmetric aurora detected in the two hemispheres simultaneously.
  • Østgaard, Nikolai; Gjesteland, Thomas; Connell, Paul H.; Stadsnes, Johan. 2009. Analysis of a subset of BATSE TGFs that do not suffer from instrumental limitations.
  • Gjesteland, Thomas; Østgaard, Nikolai; Connell, Paul H.; Stadsnes, Johan. 2009. Analysis of BATSE TGFs taking instrumental limitations into account.
  • Østgaard, Nikolai; Skogseide, Yngve; Ullaland, Kjetil; Stadsnes, Johan; Maehlum, Gunnar; Budtz-Jørgensen, Carl; Kuvvetli, Irfan; Solberg, Arne Olav; Njøten, Kåre. 2009. An X- and gamma-ray detector for observing terrestrial gamma flashes from the International Space Station.
  • Østgaard, Nikolai; Åsnes, Arne; Pedersen, A.; Borg, A.L.; Phan, T.D.; Øieroset, Marit; Snekvik, Kristian; Laundal, Karl Magnus. 2008. What are the ionospheric signatures of magnetotail reconnection?
  • Daae, Marianne; Østgaard, Nikolai; Lewis, W. 2008. Undulations on the equatorial edge of the auroral oval in the dusk sector.
  • Gjesteland, Thomas; Østgaard, Nikolai; Stadsnes, Johan; Connell, Paul H.; Carlson, Brant. 2008. The production altitude and time delays of the terrestrial gamma flashes - revisiting the BATSE spectra.
  • Østgaard, Nikolai; Gjesteland, Thomas; Stadsnes, Johan; Connell, Paul H.; Carlson, Brant. 2008. The production altitude and time delays of the terrestrial gamma flashes - revisiting the BATSE spectra.
  • Østgaard, Nikolai; Gjesteland, Thomas; Stadsnes, Johan; Connell, Paul H.; Carlson, Brant. 2008. The production altitude and time delays of the terrestrial gamma flashes - revisiting the BATSE spectra.
  • Olafsson, Kjartan; Østgaard, Nikolai. 2008. The Space Science Suitcase Instruments for Exploring Space Weather From the Classroom.
  • Stadsnes, Johan; Aksnes, Arve; Sætre, Camilla; Tyssøy, Hilde Nesse; Østgaard, Nikolai; Barth, Charles A.; Baker, Daniel N.; Bailey, Scott M.; Germany, Glynn; Mertens, Chris J.; Evand, David S.; Vondrak, Richard R.; Petrinec, Steve M. 2008. Observations of energetic particle precipitation and effects on the mesosphere and lower thermosphere.
  • Gjesteland, Thomas; Østgaard, Nikolai; Connell, Paul H.; Stadsnes, Johan. 2008. Monte Carlo simulation of the temporal behavior of Terrestrial Gamma ray Flashes and analysis of the BATSE measurements.
  • Gjesteland, Thomas; Østgaard, Nikolai; Connell, Paul H.; Stadsnes, Johan. 2008. Monte Carlo simulation of the temporal behavior of Terrestrial Gamma ray Flashes.
  • Laundal, Karl Magnus; Østgaard, Nikolai. 2008. Conjugate observations of substorm onset and expansion in the two hemispheres.
  • Laundal, Karl Magnus; Østgaard, Nikolai. 2008. Conjugate imaging of substorms.
  • Østgaard, Nikolai; Laundal, Karl Magnus. 2008. Auroral conjugacy studies.
  • Østgaard, Nikolai; Gjesteland, Thomas; Connell, Paul H.; Stadsnes, Johan. 2008. Analysis of a subset of BATSE TGFs that do not suffer from instrumental limitations.
  • Bhardwaj, A.; Østgaard, Nikolai. 2007. olar System X-rays: Relationship with Solar X-rays and Solar Wind.
  • Østgaard, Nikolai; Borg, A.L.; Åsnes, Arne; Pedersen, A.; Øieroset, Marit; Phan, T.D.; Snekvik, Kristian. 2007. What are the ionospheric signatures of magnetotail reconnection?
  • Østgaard, Nikolai; Borg, A.L.; Åsnes, Arne; Pedersen, A.; Øieroset, Marit; Phan, Tai D. 2007. What are the ionospheric signatures of magnetotail reconnection?
  • Olafsson, Kjartan; Østgaard, Nikolai; Tanskanen, Eija Irene. 2007. The Spce Suitcase - instruments for exploring the near-Earth space from the classroom.
  • Laundal, Karl Magnus; Østgaard, Nikolai. 2007. Solar wind pressure as a cause for persistent proton precipitation.
  • Gjesteland, Thomas; Østgaard, Nikolai; Stadsnes, Johan; Connell, Paul. 2007. Monte Carlo simulation of the temporal behavior of Terrestrial Gamma ray Flashes.
  • Østgaard, Nikolai. 2007. IPY-ICESTAR.
  • Orr, Astrid; Østgaard, Nikolai. 2007. ESA's Atmosphere-Space Interactions Monitor (ASIM) for the ISS.
  • Østgaard, Nikolai. 2007. Conjugate studies.
  • Østgaard, Nikolai. 2007. Conjugate studies.
  • Helland, Anders Groth; Østgaard, Nikolai; Ullaland, Kjetil; Solberg, Arne Olav; Njøten, Kåre; Reimundo, Viviana. 2007. ASIM.
  • Østgaard, Nikolai; Stadsnes, Johan. 2006. X-ray spectra measured by MXGS can reveal the production altitude of TGFs.
  • Neubert, T; Budzt-Jørgensen, C; Kuvvetli, I; Østgaard, Nikolai; Reglero, V; Arnold, N. 2006. The Atmosphere-Space Interactions Monitor (ASIM) for the International Space Station.
  • Østgaard, Nikolai; Stadsnes, Johan; Gjesteland, T; Connell, Paul. 2006. TGF production altitude - revisiting the BATSE spectra in view of upcoming missions.
  • Østgaard, Nikolai; Mende, S.B.; Frey, H.U.; Sigwarth, J.B.; Åsnes, Arne. 2006. Substorm onset asymmetries derived from conjugate auroral imaging.
  • Østgaard, Nikolai; Mende, S.B.; Frey, H.U.; Sigwarth, J.B. 2006. Simulaneous imaging of the reconnection spot in the opposite hemispheres during northward IMF.
  • Stadsnes, Johan; Aksnes, Arve; Sætre, Camilla; Østgaard, Nikolai; Barth, Charles A.; Bailey, Scott M.; Germany, Glynn. 2006. Satellite remote mapping of the precipitation of energetic electrons and their effects on the Earth's upper atmosphere.
  • Østgaard, Nikolai. 2006. Remote sensing of X rays to study characteristics of electron precipitation.
  • Østgaard, Nikolai. 2006. Imaging the upper atmopshere from space.
  • Østgaard, Nikolai; Mende, S.B.; Frey, H.U.; Sigwarth, J.B.; Åsnes, Arne; Weygand, J. 2006. ICESTAR: Auroral conjugacy studies.
  • Østgaard, Nikolai; Kauristi, K; Weatherwax, A.T. 2006. ICESTAR A connection between IHY and IPY.
  • Østgaard, Nikolai; Mende, S.B.; Frey, H.U.; Sigwarth, J.B.; Åsnes, Arne; Weygand, J. 2006. Hemispherical asymmetries derived from conjugate auroral imaging.
  • Stadsnes, Johan; Østgaard, Nikolai; Sætre, Camilla; Åsnes, Arne. 2006. Global observations of the dynamics of energetic electron precipitation during substorms.
  • Østgaard, Nikolai; Immel, T.J. 2006. Global imaging to predict space weather.
  • Østgaard, Nikolai; Mende, S.B.; Frey, H.U.; Sigwarth, J.B.; Åsnes, Arne; Weygand, J. 2006. Conjugate imaging of substorms.
  • Østgaard, Nikolai; Mende, S.B.; Frey, H.U.; Sigwarth, J.B.; Åsnes, Arne; Weygand, J. 2006. Auroral conjugacy studies based on global imaging.
  • Østgaard, Nikolai; Mende, S.B.; Frey, H.U.; Sigwarth, J.B. 2006. Auroral conjugacy studies.
  • Borg, A. L; Østgaard, Nikolai; Pedersen, A. 2005. Studies of an X-line passage 2 October 2002 using multipoint Cluster and Polar imaging data,.
  • Østgaard, Nikolai; Stadsnes, Johan. 2005. Production altitude effects on the X-ray spectrum from TGFs.
  • Østgaard, Nikolai; Stadsnes, Johan. 2005. Production altitude effects on the X-ray spectrum from TGFs.
  • Sætre, Camilla; Stadsnes, Johan; Østgaard, Nikolai. 2005. Kjemiske effekter av elektronnedbør i den lavere termosfæren.
  • Aksnes, Arve; Stadsnes, Johan; Østgaard, Nikolai; Germany, G.A.; Vondrak, R.R.; Oksavik, K.; Brekke, Asgeir; Løvhaug, Unni Pia. 2005. Ionospheric global conductance maps from remote sensing of UV and X-ray emissions.
  • Aksnes, Arve; Stadsnes, Johan; Brekke, Asgeir; Østgaard, Nikolai; Germany, G.A.; Vondrak, R.R.; Oksavik, K.; Løvhaug, Unni Pia. 2005. Height profiles of the ionospheric electron density derived from remote sensing of UV- and X-ray emissions and measured by EISCAT radar.
  • Aksnes, Arve; Stadsnes, Johan; Østgaard, Nikolai; Germany, Glynn; Oksavik, Kjellmar; Vondrak, Richard R.; Brekke, Asgeir; Løvhaug, Unni Pia. 2005. Height profiles of the ionospheric electron density derived from remote sensing of UV and X-ray emissions and measurements by the EISCAT radar: A comparison.
  • Østgaard, Nikolai; Mende, S.B.; Frey, H.U.; Sigwarth, J.B. 2005. Global imaging of Auroral Phenomena in the Conjugate Hemispheres.
  • Nesse, Hilde; Stadsnes, Johan; Paxton, Larry; Aksnes, Arve; Åsnes, Arne; Østgaard, Nikolai. 2005. Effects on the O/N2-ratio caused by ionospheric heating during geomagnetic storms.
  • Østgaard, Nikolai. 2005. Conjugate auroral observations, Now and in the future.
  • Sætre, Camilla; Stadsnes, Johan; Østgaard, Nikolai; Aksnes, Arve. 2005. Chemical effects of electron precipitation: Nitric Oxide in the lower thermosphere.
  • Østgaard, Nikolai; Mende, S.B.; Frey, H.U.; Sigwarth, J.B. 2005. Auroral signatures of lobe reconnection observed simultaneously in the conjugate hemispheres.
  • Østgaard, Nikolai; Stadsnes, Johan; Moen, J.; Gerard, Jean-Claude. 2005. A double spacecraft imaging mission to study reconnection and ion outflow.
  • Bhardwaj, A.; Elsner, R.F.; Gladstone, G.r.; Cravens, T.E.; Waite, J.H.; Branduardi-Raymont, Graziella; Østgaard, Nikolai; Dennerl, Konrad; Lisse, Casey; Kharchenko, Vasili; Hoekstra, Ronnie; Beirersdorfer, Peter. 2005. A Comparative View of X-rays from the Solar System.
  • Sætre, Camilla; Stadsnes, Johan; Aksnes, Arve; Baker, Daniel N.; Barth, Charles A.; Brekke, Asgeir; Nesse, Hilde; Petrinec, Steve M.; Nozawa, Satonori; Østgaard, Nikolai. 2004. The impact of energetic electron precipitation on nitric oxide in the upper atmosphere - Including neutral wind effects.
  • Frey, H.U.; Mende, S.B.; Immel, T.J.; Østgaard, Nikolai; Phan, T.D. 2004. The combination of auroral imaging and spacecraft in-situ measurements for M-I coupling research.
  • Frey, H.U.; Haerendel, G.; Mende, S.B.; Forrester, W.T.; Thomsen, M.; Immel, T.J.; Østgaard, Nikolai. 2004. Sub-Auroral Morning Proton Spots (SAMPS) as a result of plasmapause-ring-current interaction.
  • Stubbs, T.; Vondrak, Richard R.; Østgaard, Nikolai; Sigwarth, J.B.; Frank, L.A. 2004. Simultaneous observations of the auroral oval in both hemispheres under various conditions.
  • Frey, H.U.; Østgaard, Nikolai; Immel, T.J.; Korth, H.; Mende, S.B. 2004. Seasonal dependence of localized, High Latitude Dayside Aurora (HiLDA).
  • Kozlovsky, A.; Koustov, A.; Safargaleev, V.; Østgaard, Nikolai. 2004. Response of magnetospheric electric fields and dayside auroras to a solar wind pressure pulse.
  • Kozlovsky, A.; Koustov, A.; Safargaleev, V.; Østgaard, Nikolai. 2004. Response of dayside auroras and ionospheric plasma flows to a solar wind pressure pulse.
  • Amm, Olaf; Aksnes, Arve; Stadsnes, Johan; Østgaard, Nikolai; Vondrak, Richard R.; Germany, Glynn A.; Sillanpaa, Ian. 2004. Observations and analysis of ionospheric electrodynamics during a substorm recovery phase using the MIRACLE network.
  • Østgaard, Nikolai; Mende, S.B.; Frey, H.U.; Immel, T.J.; Frank, L.A.; Sigwarth, J.B.; Fillingim, M. 2004. IMF control of the aurora in the conjugate hemispheres.
  • Østgaard, Nikolai; Mende, S.B.; Frey, H.U.; Immel, T.J.; Frank, L.A.; Sigwarth, J.B.; Fillingim, M. 2004. IMF control of auroral phenomena in the conjugate hemispheres.
  • Immel, T.J.; Østgaard, Nikolai; Strickland, D.J.; Frey, H.U.; Mende, S.B.; Lu, G. 2004. IMAGE-FUV observations of the October-November 2003 flare and magnetic storm effects on Earth.
  • Bhardwaj, A.; Elsner, R.F.; Gladstone, G.r.; Waite, J.H.; Cravens, T.E.; Østgaard, Nikolai; Chang, S.w.; Metzger, A.E.; Majeed, T. 2004. First terrestrial soft X-ray aurora observations by Chandra.
  • Pedersen, A.; Balogh, A.; Borg, A.L.; Holtet, J.; Lybekk, B.; Moen, J.; Oksavik, K.; Østgaard, Nikolai; Svenes, K.; Søraas, Finn. 2004. Electric and magnetic field and particle observations on Cluster combined with ground-based observations during substorms.
  • Nesse, Hilde; Stadsnes, Johan; Paxton, Larry; Christensen, Andrew B; Sætre, Camilla; Åsnes, Arne; Østgaard, Nikolai. 2004. Effects on the O/N2-ratio caused by energetic electron precipitation during storms.
  • Gladstone, G.r.; Elsner, R.F.; Bhardwaj, A.; Østgaard, Nikolai; Waite, J.H.; Majeed, T.; Chang, S.w.; Cravens, T.E. 2004. Chandra observations of soft X-ray emissions from Earth and Jupiter.
  • Stadsnes, Johan; Bjordal, Jon; Østgaard, Nikolai; Aksnes, Arve; Chenette, D.L.; Parks, G.K.; Brittnacher, MJ. 2000. Temporal and Spatial Features of the Energetic Electron Precipitation During Substroms.
  • Stadsnes, Johan; Bjordal, Jon; Østgaard, Nikolai; Thorsen, Elisabeth; Chenette, D.L.; Parks, G.K.; Brittnacher, MJ. 2000. Temporal and Spatial Features of the Energetic Electron Precipitation During Substorms.
  • Stadsnes, Johan; Bjordal, Jon; Østgaard, Nikolai; Aksnes, Arve; Chenette, D.L.; Parks, G.K.; Brittnacher, MJ. 2000. Temporal and Spatial Features of the Energetic Electron Precipitation During Substorms.
  • Østgaard, Nikolai; Stadsnes, Johan; Bjordal, Jon; Germany, G.; Vondrak, RR; Chenette, D.L.; Pronko, J.G.; Cummer, S.A. 2000. Global energy input derived from UVI and PIXIE.
  • Østgaard, Nikolai; Stadsnes, Johan; Bjordal, Jon; Germany, G.; Vondrak, RR; Chenette, D.L.; Pronko, J.G.; Cummer, S.A. 2000. Global energy input derived from UVI and PIXIE.
  • Aksnes, Arve; Stadsnes, Johan; Bjordal, Jon; Østgaard, Nikolai; Detrick, D.; Rosenberg, T.; Vondrak, RR; Chenette, D.L. 2000. Global Conductivity Maps Derived From Polar PIXIE Observations.
  • Østgaard, Nikolai; Stadsnes, Johan; Germany, G.; Vondrak, RR. 2000. Energy Analysis of an Isolated Substorm Based on Remote Sensing Techniques.
  • Håland, Stein; Østgaard, Nikolai; Bjordal, Jon; Stadsnes, Johan; Ullaland, Stein; Wilken, B; Yamamoto, T; Doke, T.; Chenette, D.L.; Parks, G.K.; Brittnacher, MJ; Reeves, G.D. 2000. Energetic Particle Signatures of Reconnection and Plasmoid Formation in the Magnetotail.
  • Håland, Stein; Østgaard, Nikolai; Stadsnes, Johan; Søraas, Finn; Germany, G.; Vondrak, RR; Wilken, B; Doke, T. 2000. Comparison of energy spectra in the ionosphere and in the central plasma sheet during a magnetospheric substorm.

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