• The asymmetric geospace as displayed during the geomagnetic storm on 17 August 2001 

      Østgaard, Nikolai; Reistad, Jone Peter; Tenfjord, Paul; Laundal, Karl Magnus; Rexer, Theresa; Haaland, Stein; Snekvik, Kristian; Hesse, Michael; Milan, Stephen Eric; Ohma, Anders (Peer reviewed; Journal article, 2018-11-29)
      Previous studies have shown that conjugate auroral features are displaced in the two hemispheres when the interplanetary magnetic field (IMF) has a transverse (Y) component. It has also been shown that a BY component is ...
    • Characteristics of fragmented aurora-like emissions (FAEs) observed on Svalbard 

      Dreyer, Joshua; Partamies, Noora; Whiter, Daniel; Ellingsen, Pål Gunnar; Baddeley, Lisa; Buchert, Stephan C. (Journal article; Peer reviewed, 2021)
      This study analyses the observations of a new type of small-scale aurora-like feature, which is further referred to as fragmented aurora-like emission(s) (FAEs). An all-sky camera captured these FAEs on three separate ...
    • Electron precipitation characteristics during isolated, compound, and multi-night substorm events 

      Partamies, Noora; Tesema, Fasil; Bland, Emma; Heino, Erkka; Tyssøy, Hilde Nesse; Kallelid, Erlend Salte (Journal article; Peer reviewed, 2021)
      A set of 24 isolated, 46 compound, and 36 multi-night substorm events from the years 2008–2013 have been analysed in this study. Isolated substorm events are defined as single expansion–recovery phase pairs, compound ...
    • Estimating the fate of oxygen ion outflow from the high-altitude cusp 

      Krcelic, Patrik; Haaland, Stein; Maes, Lukas; Slapak, Rikard; Schillings, Audrey (Journal article; Peer reviewed, 2020)
      We have investigated the oxygen escape-to-capture ratio from the high-altitude cusp regions for various geomagnetic activity levels by combining EDI and CODIF measurements from the Cluster spacecraft. Using a magnetic field ...
    • An investigation into the spectral parameters of ultra-low-frequency (ULF) waves in the polar caps and magnetotail 

      Nosikova, Nataliya Sergeevna; Yagova, Nadezda Viktorovna; Baddeley, Lisa; Lorentzen, Dag Arne; Sormakov, Dmitriy Anatolyevich (Journal article; Peer reviewed, 2022)
      The present case study is focused on fluctuations at ∼ 1.5 mHz observed on open field lines in both of the polar caps in ground-based geomagnetic data and in the electron concentration in the Northern Hemisphere ionosphere. ...
    • Lower-thermosphere–ionosphere (LTI) quantities: current status of measuring techniques and models 

      Palmroth, Minna; Grandin, Maxime; Sarris, Theodoros E.; Doornbos, Eelco; Tourgaidis, Stylianos; Aikio, Anita; Buchert, Stephan C.; Clilverd, Mark A.; Dandouras, I; Heelis, Roderick A.; Hoffmann, A; Ivchenko, N.; Kervalishvili, G.; Knudsen, D.; Kotova, A; Liu, H.-L.; Malaspina, D; March, G.; Marchaudon, A; Marghitu, Octav; Matsuo, T; Miloch, Wojciech Jacek; Moretto, Therese; Mpaloukidis, D; Olsen, NIls; Pfaff, R.; Papadakis, K; Pirnaris, Panagiotis; Siemes, C.; Stolle, Claudia; Suni, J.; van den IJssel, J.; Verronen, Pekka T.; Visser, P.; Yamauchi, Masatoshi (Journal article; Peer reviewed, 2021)
      The lower-thermosphere–ionosphere (LTI) system consists of the upper atmosphere and the lower part of the ionosphere and as such comprises a complex system coupled to both the atmosphere below and space above. The atmospheric ...
    • Observations of precipitation energies during different types of pulsating aurora 

      Kebede, Fasil Tesema; Partamies, Noora; Tyssøy, Hilde Nesse; McKay, Derek (Journal article; Peer reviewed, 2020)
      Pulsating aurora (PsA) is a diffuse type of aurora with different structures switching on and off with a period of a few seconds. It is often associated with energetic electron precipitation (>10 keV) resulting in the ...
    • Observations of sunlit N2+ aurora at high altitudes during the RENU2 flight 

      Ellingsen, Pål Gunnar; Lorentzen, Dag Arne; Kenward, David; Hecht, James H.; Evans, J. Scott; Sigernes, Fred; Lessard, Marc (Journal article; Peer reviewed, 2021)
      We present measurements of sunlit aurora during the launch of the Rocket Experiment for Neutral Upwelling 2 (RENU2) on the 13 December 2015, 07:34 UTC. The in situ auroral conditions coincide with those of sunlit aurora ...
    • 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 red-sky enigma over Svalbard in December 2002 

      Sigernes, Fred; Lloyd, N.; Lorentzen, Dag Arne; Neuber, R.; Hoppe, U.-P.; Degenstein, D.; Shumilov, N.; Moen, Jøran Idar; Gjessing, Yngvar; Havnes, Ove; Skartveit, Arvid; Raustein, Elmer; Ørbæk, J.B.; Deehr, CS (Peer reviewed; Journal article, 2005)
      On 6 December 2002, during winter darkness, an extraordinary event occurred in the sky, as viewed from Longyearbyen (78° N, 15° E), Svalbard, Norway. At 07:30 UT the southeast sky was surprisingly lit up in a deep red ...
    • Simulated seasonal impact on middle atmospheric ozone from high-energy electron precipitation related to pulsating aurorae 

      Verronen, Pekka T.; Kero, Antti; Partamies, Noora; Szelag, Monika E.; Oyama, Shin-Ichiro; Miyoshi, Yoshizumi; Turunen, Esa (Journal article; Peer reviewed, 2021)
      Recent simulation studies have provided evidence that a pulsating aurora (PsA) associated with high-energy electron precipitation is having a clear local impact on ozone chemistry in the polar middle mesosphere. However, ...
    • Types of pulsating aurora: Comparison of model and EISCAT electron density observations 

      Tesema, Fasil; Partamies, Noora; Whiter, Daniel K.; Ogawa, Yasunobu (Journal article; Peer reviewed, 2022)
      Energetic particle precipitation associated with pulsating aurora (PsA) can reach down to lower mesospheric altitudes and deplete ozone. It is well documented that pulsating aurora is a common phenomenon during substorm ...