Nikolai Østgaard's picture
Nikolai
Østgaard
Professor
Visit Address: 
Allegt. 55
5007 BERGEN
Postal Address: 
Postboks 7803
5007 BERGEN
Phone: 
+47 55 58 27 94
+47 472 70 653
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Journal articles
  • Hansen, Ragnhild Schrøder; Østgaard, Nikolai; Gjesteland, Thomas; Carlson, Brant Edward. 2013. How simulated fluence of photons from terrestrial gamma ray flashes at aircraft and balloon altitudes depends on initial parameters. Journal of Geophysical Research. 118: 2333-2339. doi: 10.1002/jgra.50143
  • Reistad, Jone Peter; Østgaard, Nikolai; Laundal, Karl Magnus; Oksavik, Kjellmar. 2013. On the non-conjugacy of nightside aurora and their generator mechanisms. Journal of Geophysical Research - Space Physics. 118: 3394-3406. doi: 10.1002/jgra.50300
  • Tenfjord, Paul; Østgaard, Nikolai. 2013. Energy transfer and flow in the solar wind-magnetosphere-ionosphere system: A new coupling function. Journal of Geophysical Research - Space Physics. 118: 5659-5672. doi: 10.1002/jgra.50545
  • Østgaard, Nikolai; Gjesteland, Thomas; Carlson, Brant Edward; Collier, Andrew B.; Cummer, Steven A.; Lu, Gaopeng; Christian, Hugh J. 2013. Simultaneous observations of optical lightning and terrestrial gamma ray flash from space. Geophysical Research Letters. 40: 2423-2426. doi: 10.1002/grl.50466
  • Østgaard, Nikolai; Laundal, Karl Magnus; Humberset, Beate Krøvel. 2013. Correction to 'Evolution of auroral asymmetries in the conjugate hemispheres during two substorms.'. Geophysical Research Letters. 40: 471-471. doi: 10.1029/2012GL055020
  • Berthomier, M; Fazakerley, Andrew N.; Forsyth, C; Pottelette, R; Alexandrova, O; Anastasiadis, A; Aruliah, A; Blelly, PL; Briand, C; Bruno, R; Canu, P; Cecconi, B; Chust, T; Daglis, I; Davies, J; Dunlop, M; Fontaine, D; Genot, V; Gustavsson, B; Haerendel, G; Hamrin, M; Hapgood, M; Hess, S; Kataria, D; Kauristie, K; Kemble, S; Khotyaintsev, Y; Koskinen, H; Lamy, L; Lanchester, B; Louarn, P; Lucek, E; Lundin, R; Maksimovic, M; Manninen, J; Marchaudon, A; Marghitu, O; Marklund, G; Milan, S; Moen, Jøran Idar; Mottez, F; Nilsson, H; Østgaard, Nikolai; Owen, CJ; Parrot, M; Pedersen, Arne; Perry, C; Pincon, JL; Pitout, F; Pulkkinen, T; Rae, IJ; Rezeau, L; Roux, A; Sandahl, I; Sandberg, I; Turunen, E; Vogt, J; Walsh, A; Watt, CEJ; Wild, JA; Yamauchi, M; Zarka, P; Zouganelis, I. 2012. Alfven: magnetosphere-ionosphere connection explorers. Experimental astronomy (Print). 33: 445-489. doi: 10.1007/s10686-011-9273-y
  • Carlson, Brant Edward; Gjesteland, Thomas; Østgaard, Nikolai. 2012. Connecting the terrestrial gamma-ray flash source strength and observed fluence distributions. Journal of Geophysical Research - Space Physics. 117. Published 2012-01-21. doi: 10.1029/2011JA017122
  • Cenkeramaddi, Linga Reddy; Genov, Georgi; Kohfeldt, Anja; Njøten, Kåre; Rostad, Maja Elise; Skogseide, Yngve; Roscoe, Magnus Lode; Solberg, Arne Olav; Stadsnes, Johan; Ullaland, Kjetil; Østgaard, Nikolai; Budtz-Jørgensen, Carl; Kuvvetli, Irfan; Mikkelsen, Sindre; Mæhlum, Gunnar. 2012. Low-energy CZT detector array for the ASIM mission. IEEE Instrumentation and Measurement Technology Conference. Proceedings. 2119-2123.
  • Gjesteland, Thomas; Østgaard, Nikolai; Collier, Andrew B.; Carlson, Brant Edward; Eyles, Chris J.; Smith, David M. 2012. A new method reveals more TGFs in the RHESSI data. Geophysical Research Letters. 39. 5 pages. doi: 10.1029/2012GL050899
  • Haaland, Stein; Eriksson, Anders; Engwall, Erik; Lybekk, Bjørn; Nilsson, Hans; Pedersen, Arne; Svenes, Knut Ragnar; André, Mats; Förster, Matthias; Li, K.; Johnsen, Christine; Østgaard, Nikolai. 2012. Estimating the capture and loss of cold plasma from ionospheric outflow. Journal of Geophysical Research - Space Physics. 117. 11 pages. doi: 10.1029/2012JA017679
  • Milan, Steve E.; Dunlop, Malcolm W.; Fazakerley, A; Hubert, Benoit; Lavraud, Benoit; Østgaard, Nikolai; Shi, J; Escoubet, C. P.; Taylor, M; Falkner, P; Wielders, A. 2012. KuaFu Sun-Earth connection explorer. Astronomy & Geophysics.
  • Skogseide, Yngve; Cenkeramaddi, Linga Reddy; Genov, Georgi; Njøten, Kåre; Rostad, Maja Elise; Solberg, Arne Olav; Stadsnes, Johan; Ullaland, Kjetil; Østgaard, Nikolai; Budtz-Jørgensen, Carl; Kuvvetli, Irfan. 2012. BGO front-end electronics and signal processing in the MXGS instrument for the ASIM mission. IEEE Instrumentation and Measurement Technology Conference. Proceedings. 2124-2127.
  • Snekvik, Kristian; Tanskanen, Eija Irene; Østgaard, Nikolai; Juusola, Liisa; Laundal, Karl Magnus; Gordeev, Evigini I.; Borg, Anette Lauen. 2012. Changes in the magnetotail configuration before near-Earth reconnection. Journal of Geophysical Research - Space Physics. 117. 12 pages. doi: 10.1029/2011JA017040
  • Østgaard, Nikolai; Gjesteland, Thomas; Hansen, Ragnhild Schrøder; Collier, Andrew B.; Carlson, Brant Edward. 2012. The true fluence distribution of terrestrial gamma flashes at satellite altitude. Journal of Geophysical Research - Space Physics. 117. 8 pages. doi: 10.1029/2011JA017365
  • Østgaard, Nikolai; Laundal, Karl Magnus; Juusola, Liisa; Aasnes, A.; Haaland, S.; Weygand, James M. 2012. Correction to 'Interhemispherical asymmetry of substorm onset locations and the Interplanetary Magnetic Field.'. Geophysical Research Letters. 39.
  • Carlson, Brant Edward; Gjesteland, Thomas; Østgaard, Nikolai. 2011. Terrestrial gamma-ray flash electron beam geometry, fluence, and detection frequency. Journal of Geophysical Research - Space Physics. 116. Published 2011-11-19. doi: 10.1029/2011JA016812
  • Collier, Andrew B.; Gjesteland, Thomas; Østgaard, Nikolai. 2011. Assessing the power law distribution of TGFs. Journal of Geophysical Research - Space Physics. 116. 18 pages. doi: 10.1029/2011JA016612
  • Gjesteland, Thomas; Østgaard, Nikolai; Collier, A. B.; Carlson, Brant Edward; Cohen, M. B.; Lehtinen, N. G. 2011. Confining the angular distribution of terrestrial gamma ray flash emission. Journal of Geophysical Research - Space Physics. 116. 8 pages. doi: 10.1029/2011JA016716
  • Juusola, Liisa; Østgaard, Nikolai; Tanskanen, Eija Irene. 2011. Statistics of plasma sheet convection. Journal of Geophysical Research - Space Physics. 116. 12 pages. doi: 10.1029/2011JA016479
  • Juusola, Liisa; Østgaard, Nikolai; Tanskanen, Eija Irene; Partamies, N.; Snekvik, K. 2011. Earthward plasma sheet flows during substorm phases. Journal of Geophysical Research - Space Physics. 116. 11 pages. doi: 10.1029/2011JA016852
  • Østgaard, Nikolai; Humberset, Beate Krøvel; Laundal, Karl Magnus. 2011. Evolution of auroral asymmetries in the conjugate hemispheres during two substorms. Geophysical Research Letters. 38. 6 pages. doi: 10.1029/2010GL046057
  • Østgaard, Nikolai; Laundal, Karl Magnus; Juusola, Liisa; Åsnes, Arne; Haaland, Stein; Weygand, James M. 2011. Interhemispherical asymmetry of substorm onset locations and the interplanetary magnetic field. Geophysical Research Letters. 38. 5 pages. doi: 10.1029/2011GL046767
  • Frey, H. U.; Amm, O.; Chaston, C. C.; Fu, S.; Haerendel, G.; Juusola, Liisa; Karlsson, T.; Lanchester, B.; Nakamura, R.; Østgaard, Nikolai; Sakanoi, T.; Séran, E.; Whiter, D.; Weygand, J.; Asamura, K.; Hirahara, M. 2010. Small and meso-scale properties of a substorm onset auroral arc. Journal of Geophysical Research - Space Physics. 115. 20 pages. doi: 10.1029/2010JA015537
  • Gjesteland, Thomas; Østgaard, Nikolai; Connell, Paul H.; Stadsnes, Johan; Fishman, Gerald J. 2010. Effects of dead time losses on terrestrial gamma ray flash measurements with the Burst and Transient Source Experiment. Journal of Geophysical Research - Space Physics. 115. 10 pages. doi: 10.1029/2009JA014578
  • Laundal, Karl Magnus; Østgaard, Nikolai; Frey, H. U.; Weygand, J. 2010. Seasonal and interplanetary magnetic field-dependent polar cap contraction during substorm expansion phase. Journal of Geophysical Research - Space Physics. 115: A11224. doi: 10.1029/2010JA015910
  • Laundal, Karl Magnus; Østgaard, Nikolai; Snekvik, Kristian; Frey, Harald U. 2010. Interhemispheric observations of emerging polar cap asymmetries. Journal of Geophysical Research - Space Physics. 115. 15 pages. doi: 10.1029/2009JA015160
  • Budtz-Jorgensen, Carl; Kuvvetli, Irfan; Skogseide, Yngve; Ullaland, Kjetil; Østgaard, Nikolai. 2009. Characterization of CZT Detectors for the ASIM Mission. IEEE Transactions on Nuclear Science. 56: 1842-1847. doi: 10.1109/TNS.2009.2021423
  • Laundal, Karl Magnus; Østgaard, Nikolai. 2009. Asymmetric auroral intensities in the Earth's Northern and Southern hemispheres. Nature. 460: 491-493. doi: 10.1038/nature08154
  • Olafsson, Kjartan; Østgaard, Nikolai; Tanskanen, Eija Irene. 2009. The Space Science Suitcase - Instruments for Exploring Near-Earth Space from the Classroom. Earth, moon, and planets. 104: 73-75. doi: 10.1007/s11038-008-9261-z
  • Renard, J-B; Berthet, G; Catoire, V; Østgaard, Nikolai. 2009. COBRAT project: Long duration balloons for the study of high energy phenomena and consequence for stratospheric chemistry,. MarinLab.
  • Snekvik, Kristian; Juusola, Liisa; Østgaard, Nikolai; Amm, Olaf. 2009. Reconnection Hall current system observed in the magnetotail and in the ionosphere. Geophysical Research Letters. 36. doi: 10.1029/2009GL037239
  • Østgaard, Nikolai; Ostgaard, N; Snekvik, Kristian; Borg, Anette Lauen; Åsnes, Arne; Asnes, A; Pedersen, Arne; Øieroset, Marit; Oieroset, M; Phan, Tai D.; Phan, T; Haaland, Stein. 2009. Can magnetotail reconnection produce the auroral intensities observed in the conjugate ionosphere? Journal of Geophysical Research - Space Physics. 114. 13 pages. doi: 10.1029/2009JA014185
  • Laundal, Karl Magnus; Østgaard, Nikolai. 2008. Persistent global proton aurora caused by high solar wind dynamic pressure. Journal of Geophysical Research. 113. 8 pages. doi: 10.1029/2008JA013147
  • Mikkelsen, S; Meier, D; Mæhlum, G; Sundal, B; Talebi, J; Helland, Anders Groth; Østgaard, Nikolai; Skogseide, Yngve; Ullaland, Kjetil. 2008. Low-Power and Low-Noise Multi Channel ASIC for X-ray and Gamma-Ray Spectrosopy. MarinLab.
  • Olafsson, Kjartan; Østgaard, Nikolai; Tanskanen, Eija Irene. 2008. The Space Science Suitcase - Instruments for exploring Near-Earth Space from Classroom. Earth, moon, and planets. doi: 10.1007/s11038-008-9261-z
  • Snekvik, Kristian; Nakamura, Rumi; Østgaard, Nikolai; Haaland, Stein; Retinò, Alessandro. 2008. The Hall current system revealed as a statistical significant pattern during fast flows. Annales Geophysicae. 26: 3429-3437.
  • Østgaard, Nikolai; Gjesteland, Thomas; Stadsnes, Johan; Connell, Paul H.; Carlson, Bran. 2008. Production altitude and time delays of the terrestrial gamma flashes: Revisiting the Burst and Transient Source Experiment spectra. Journal of Geophysical Research. 113. 14 pages. doi: 10.1029/2007JA012618
  • Bhardwaj, Anil; Elsner, Ronald F.; Gladstone, G. Randall; Cravens, Thomas E.; Lisse, Casey; Dennerl, Konrad; Branduardi-Raymont, Graziella; Wargelin, BJ; Waite, J. Hunter; Robertson, Ina; Østgaard, Nikolai; Beiersdorfer, Peter; Snowden, SL; Kharchenko, Vasili. 2007. X-rays from solar system objects. Planetary and Space Science. 55: 1135-1189. doi: 10.1016/j.pss.2006.11.009
  • Bhardwaj, Anil; Gladstone, G. Randall; Elsner, Ronald F.; Østgaard, Nikolai; Waite, J. Hunter; Cravens, Thomas E.; Chang, Shen-Wu; Majeed, Thariq; Metzger, Albert E. 2007. First terrestrial soft X-ray auroral observation by the Chandra X-ray Observatory. Journal of Atmospheric and Solar-Terrestrial Physics. 69: 179-187. doi: 10.1016/j.jastp.2006.07.011
  • Borg, Anne; Ostgaard, N; Østgaard, Nikolai; Pedersen, Arne; Øieroset, Marit; Oieroset, M; Phan, Tai D.; Germany, Glynn; Aasnes, A; Åsnes, Arne; Lewis, Wilma; Stadsnes, Johan; Lucek, Elizabeth A.; Reme, Henri; Mouikis, Chris. 2007. Simultaneous observations of magnetotail reconnection and bright X-ray aurora on 2 October 2002. Journal of Geophysical Research. 112. doi: 10.1029/2006JA011913
  • Snekvik, Kristian; Haaland, Stein; Østgaard, Nikolai; Hasegawa, Hideki; Nakamura, Rumi; Takada, Toshikazu; Juusola, Liisa; Amm, Olaf; Pitout, Frederic; Rème, Henri; Klecker, Berndt; Lucek, Elizabeth A. 2007. Cluster observations of a field aligned current at the dawn flank of a bursty bulk flow. Annales Geophysicae. 25: 1405-1415.
  • Sætre, Camilla; Barth, Charles A.; Stadsnes, Johan; Østgaard, Nikolai; Bailey, Scott M.; Baker, Daniel N.; Germany, Glynn A.; Gjerloev, Jesper W. 2007. Thermospheric nitric oxide at higher latitudes: Model calculations with auroral energy input. Journal of Geophysical Research. 112. 11 pages. doi: 10.1029/2006JA012203
  • Østgaard, Nikolai; Mende, Stephen B.; Frey, Harald U.; Sigwarth, John B.; Åsnes, Arne; Weygand, James M. 2007. Auroral conjugacy studies based on global imaging. Journal of Atmospheric and Solar-Terrestrial Physics. 69: 249-255. doi: 10.1016/j.jastp.2006.05.026
  • Aksnes, Arve; Stadsnes, Johan; Østgaard, Nikolai; Germany, G. A.; Oksavik, Kjellmar; Vondrak, Richard R.; Brekke, Asgeir; Løvhaug, Unni Pia. 2006. Height profiles of the ionospheric electron density derived using space-based remote sensing of UV and X ray emissions and EISCAT radar data: A ground-truth experiment. Journal of Geophysical Research. 111.
  • Sætre, Camilla; Barth, Charles A.; Stadsnes, Johan; Østgaard, Nikolai; Bailey, Scott M.; Baker, Daniel N.; Gjerloev, Jesper W. 2006. Comparisons of electron energy deposition derived from observations of lower thermospheric nitric oxide and from X-ray bremsstrahlung measurements. Journal of Geophysical Research. 111. doi: 10.1029/2005JA011391
  • Tanskanen, Eija I.; Palmroth, Minna; Pulkkinen, Tuija I.; Koskinen, Hannu E.J.; Janhunen, Pekka; Østgaard, Nikolai; Slavin, James Arthur; Liou, Kan. 2006. Energetics of a substorm on 15 august, 2001: comparing empirical methods and a global MHD simulation. Advances in Space Research. 36: 1825-1829. doi: 10.1016/j.asr.2004.05.013
  • Aksnes, Arve; Amm, Olaf; Stadsnes, Johan; Østgaard, Nikolai; Germany, Glynn A.; Vondrak, Richard R.; Sillanpää, Ian; Viljanen, A. 2005. Ionospheric conductances derived from satellite measurements of auroral UV and X-ray emissions, and ground-based electromagnetic data: A comparison. Annales Geophysicae. 23: 343-358.
  • Amm, Olaf; Aksnes, Arve; Stadsnes, Johan; Østgaard, Nikolai; Vondrak, Richard R.; Germany, Glynn A.; Lu, Gang; Viljanen, Ari. 2005. Mesoscale ionospheric electrodynamics of omega bands determined from ground-based electromagnetic and satellite optical observation. Annales Geophysicae. 23: 325-342.
  • Kozlovsky, A.; Safargaleev, V.; Østgaard, Nikolai; Turunen, T.; Koustov, A.; Jussila, J.; Roldugin, A. 2005. On the motion of dayside auroras caused by a solar wind pressure pulse. Annales Geophysicae. 23: 509-521.
  • Palmroth, M.; Janhunen, P.; Pulkkinen, T.I.; Aksnes, Arve; Lu, Gang; Østgaard, Nikolai; Watermann, Jorgen; Reeves, Geoff; Germany, G.A. 2005. Assessment of ionospheric Joule heating by GUMICS-4 MHD simulation, AMIE, and satellite-based statistics: Towards a synthesis. Annals of Geophysics. 23: 2051-2068.
  • Stubbs, T.; Vondrak, Richard R.; Østgaard, Nikolai; Sigwarth, J.B.; Frank, L.A. 2005. Simultaneous observations of the auroral oval in both hemispheres under varying conditions. Geophysical Research Letters. 32. doi: 10.1029/2004GL021199
  • Åsnes, Arne; Friedel, R.; Stadsnes, Johan; Thomsen, M.; Østgaard, Nikolai; Cayton, T. 2005. Statistical pitch angle properties of substorm-injected electron clouds and their relation to dawnside energetic electron precipitation. Journal of Geophysical Research. 110. doi: 10.1029/2004JA010838
  • Åsnes, Arne; Stadsnes, Johan; Friedel, R.; Østgaard, Nikolai; Thomsen, M. 2005. Medium energy pitch anglke distribution during substorm injected electron cloud. Geophysical Research Letters. 32. doi: 10.1029/2004GL022008
  • Østgaard, Nikolai; Aksnes, Arve. 2005. Været i vårt nære verdensrom. Bergens Tidende. 1 pages.
  • Østgaard, Nikolai; Aksnes, Arve. 2005. Romværet i vårt nære verdensrom. Bergens Tidende.
  • Østgaard, Nikolai; Mende, S.B.; Frey, H.U.; Sigwarth, J.B. 2005. Simultaneous imaging of the reconnection spot in the conjugate hemispheres during northward IMF. Geophysical Research Letters. 32. doi: 10.1029/2005GL024491
  • Østgaard, Nikolai; Moen, Jøran Idar; Mende, Stephan B.; Frey, Harald U.; Immel, Thomas J.; Gallop, Paul; Oksavik, Kjellmar; Fujimoto, Masaki. 2005. Estimates of magnetotail reconnection rate based on IMAGE FUV and EISCAT measurements. Annals of Geophysics. 23: 123-134.
  • Østgaard, Nikolai; Tsyganenko, Nikolai; Mende, S.B.; Frey, H.U.; Immel, T.J.; Fillingim, M.; Frank, L.A.; Sigwarth, J.B. 2005. Observations and model predictions of substorm auroral asymmetries in the conjugate hemispheres. Geophysical Research Letters. 32: L05111. doi: 10.1029/2004GL022166
  • Aksnes, Arve; Stadsnes, Johan; Lu, Gang; Østgaard, Nikolai; Vondrak, Richard R.; Detrick, Dan; Rosenberg, Ted; Germany, Glynn A.; Schulz, Mike. 2004. Effects of energetic electrons on the electrodynamics in the ionosphere. Annales Geophysicae. 22: 475-496.
  • Farrugia, C.J.; Sandholt, P.E.; Torbert, R.B.; Østgaard, Nikolai. 2004. Temporal and spatial aspects of the cusp inferred from local and global ground- and space-based observations in a case study. Journal of Geophysical Research. 109. doi: 10.1029/2003JA010121
  • Farrugia, C.J.; Sandholt, Per Even; Torbert, R. B.; Østgaard, Nikolai. 2004. Temporal and spatial aspects of the cusp inferred from local and global ground- and space-based observations in a case study. Journal of Geophysical Research. 109: art. no.-A04209. doi: 10.1029/2003JA010121
  • Frey, H.U.; Haerendel, G.; Mende, S.B.; Forrester, W.T.; Immel, T.J.; Østgaard, Nikolai. 2004. Sub-auroral morning proton spots (SAMPS) as a result of plasmapause-ring current interaction. Journal of Geophysical Research. 109. doi: 10.1029/2004JA010516
  • Frey, H.U.; Østgaard, Nikolai; Immel, T.J.; Korth, H.; Mende, S.B. 2004. Seasonal dependence of localized, High Latitude Dayside Aurora (HiLDA). Journal of Geophysical Research. 109. doi: 10.1029/2003JA010293
  • Sætre, Camilla; Stadsnes, Johan; Nesse, H; Aksnes, Arve; Petrinec, SM; Barth, CA; Baker, DN; Vondrak, Richard R.; Østgaard, Nikolai. 2004. Energetic electron precipitation and the NO abundance in the upper atmosphere: A direct comparison during a geomagnetic storm. Journal of Geophysical Research. 109. 9 pages.
  • Åsnes, Arne; Stadsnes, Johan; Bjordal, J.; Østgaard, Nikolai; Detrick, D.; Rosenberg, T.J.; Haaland, S.E.; Haaland, S. 2004. Pi2-pulsations observed in energetic electron precipitation and magnetic field in association with a substorm surge. Annales Geophysicae. 22: 2097-2105.
  • Østgaard, Nikolai; Mende, S.B.; Frey, H.U.; Immel, T.J.; Frank, L.A.; Sigwarth, J.B.; Stubbs, T. 2004. Interplanetary magnetic field control of the location of substorm onset and auroral features in the conjugate hemispheres. Journal of Geophysical Research. 109. doi: 10.1029/2003JA010370
  • Østgaard, Nikolai; Germany, Glynn A.; Stadsnes, Johan; Vondrak, Richard R. 2002. Energy analysis of substorms based on remote sensing techniques, solar wind measurements and geomagnetic indices. Journal of Geophysical Research. 107.
  • Bjordal, Jon; Borovkov, L.P.; Kornilov, I.A.; Kornilova, T.A.; Lazutin, L.L.; Østgaard, Nikolai; Stadsnes, Johan; Starkov, GV; Thorsen, Elisabeth; Chernous, S.A. 2000. Structure of polar aurora over Kola Peninsula and of X-Ray oval measured by PIXIE/POLAR on February 9, 1997. Geomagnetism and Aeronomy. 3.
  • Cummer, S.A.; Vondrak, RR; Østgaard, Nikolai; Stadsnes, Johan; Bjordal, Jon; Chenette, D.L.; Brittnacher, MJ; Parks, G.K.; Sigwarth, J.B.; Frank, L.A. 2000. Global Multispectral Auroral Imaging of an Isolated Substorm. Geophysical Research Letters. 27: 637-640.
  • Østgaard, Nikolai; Stadsnes, Johan; Bjordal, Jon; Vondrak, RR; Cummer, S.A.; Chenette, D.L.; Schulz, M.; Pronko, J.G. 2000. Cause of the localized maximum of X-ray emission in the morning sector: A comparison with electron measurements. Journal of Geophysical Research. 105: 20869-20884.
  • Østgaard, Nikolai; Stadsnes, Johan; Bjordal, Jon; Vondrak, RR; Cummer, S.A.; Chenette, D.L.; Schulz, M.; Pronko, J.G.; Parks, G.K.; Brittnacher, MJ; McKenzie, D.L. 2000. Global X-ray emission during an isolated substorm - a case study. Journal of Atmospheric and Solar-Terrestrial Physics. 62: 889-900.
  • Østgaard, Nikolai; Stadsnes, Johan; Aarsnes, Kjell; Søraas, Finn; Måseide, K.; Smith, M.; Sharber, J. 1998. Simultaneous measurements of x-rays and electrons during a pulsating aurora. Annales Geophysicae. 16: 148-160.
Reports and theses
  • Håland, Stein; Østgaard, Nikolai. 2000. Multi-spacecraft study of a megnetospheric substorm. Space Reserch in Norway. Norwegian Space Center, Oslo. 2 pages.
  • Østgaard, Nikolai; Stadsnes, Johan; Bjordal, Jon. 2000. PIXIE measurements compared with directly measured electrons. Space Reserch in Norway. Norwegian Space Center, Oslo. 2 pages.
Book sections
  • Bhardwaj, Anil; Elsner, Ronald F.; Gladstone, G. Randall; Branduardi-Raymont, Graziella; Dennerl, Konrad; Lisse, Carey M; Cravens, Thomas E.; Waite, J. Hunter; Østgaard, Nikolai; Petrinec, Steven M.; Wargelin, Bradford J; Robertson, Ina; Beiersdorfer, Peter; Snowden, Steven L; Kharchenko, Vasili. 2009. X-ray emission from planets and comets:Relationship with SOLAR X-RAYS and SOLAR WIND. -, pages 229-244. In:
    • Bhardwaj, Anil. 2009. Planetary Science. World Scientific. 380 pages. ISBN: 9789812836229.

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