• The auroral red line polarisation: modelling and measurements 

      Lilensten, J.; Bommier, V.; Barthelemy, M; Lamy, Herve; Bernard, D; Moen, Jøran Idar; Johnsen, Magnar Gullikstad; Løvhaug, Unni Pia; Pitout, Frederic (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-08-12)
      In this work, we model the polarisation of the auroral red line using the electron impact theory developed by Bommier et al. (2011). This theory enables the computation of the distribution of the Degree of Linear Polarisation (DoLP) as a function of height if the flux of precipitated electrons is provided as input. An electron transport code is used to infer the stationary electron flux at each ...
    • 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 (Journal article; Tidsskriftartikkel; Peer reviewed, 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 model development. The local relevance in Europe for studies of the ionosphere at high latitude is described. We propose as possible a way forward to sustain space weather research ...
    • Interferometric Study of Ionospheric Plasma Irregularities in Regions of Phase Scintillations and HF Backscatter 

      Spicher, Andres; LaBelle, James; Bonnell, John W.; Roglans, Roger; Moser, Chrystal; Fuselier, Stephen A.; Bounds, Scott; Clausen, Lasse; Di Mare, Francesca; Feltman, Connor A.; Jin, Yaqi; Kletzing, Craig; Miloch, Wojciech Jacek; Moen, Jøran Idar; Oksavik, Kjellmar; Sawyer, Rhyan; Takahashi, Toru; Yeoman, Tim K. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-08)
      We investigate the nature of small-scale irregularities observed in the cusp by the Twin Rockets to Investigate Cusp Electrodynamics-2 (TRICE-2) in regions of enhanced phase scintillations and high-frequency coherent radar backscatter. We take advantage of the fact that the irregularities were detected by spatially separated probes, and present an interferometric analysis of both the observed electron ...
    • Ionospheric Flow Vortex Induced by the Sudden Decrease in the Solar Wind Dynamic Pressure 

      Jin, Yaqi; Moen, Jøran Idar; Spicher, Andres; Liu, Jianjun; Clausen, Lasse; Miloch, Wojciech Jacek (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-30)
      Abrupt changes in the solar wind dynamic pressure can greatly affect the Earth's magnetosphere-ionosphere system. We present an ionospheric flow vortex in the morning sector during the sudden decrease in the solar wind dynamic pressure. The flow vortex was clearly observed by both the Hankasalmi radar and the azimuthal scan mode of the European Incoherent Scatter (EISCAT) Svalbard Radar (ESR). The ...
    • On the symmetry of ionospheric polar cap patch exits around magnetic midnight 

      Moen, Jøran Idar; Gulbrandsen, Njål; Clausen, Lasse Boy Novock (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-07-14)
      In this paper we examine how polar cap patches, which have been frozen into the antisolar flow over the polar cap, are transported into the nighttime auroral oval. First we present a detailed case study from 12 January 2002, with continuous observations of polar cap patches exiting into the nighttime auroral oval in the Scandinavian sector. Satellite images of the auroral oval and all-sky camera ...
    • Statistical Distribution of Decameter Scale (50 m) Ionospheric Irregularities at High Latitudes 

      Jin, Yaqi; Clausen, Lasse; Spicher, Andres; Ivarsen, Magnus Fagernes; Zhang, Yongliang; Miloch, Wojciech Jacek; Moen, Jøran Idar (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-15)
      We present a study of decameter scale ionospheric irregularities using in-situ electron density data from the NorSat-1 satellite. During the current period of low solar activity, NorSat-1 frequently observes significant plasma irregularities from several 10 s km down to several decameter. These are often observed near the dayside cusp and dawnside auroral zone. The decameter-scale irregularities are ...
    • Suppression of ionospheric irregularity due to auroral particle impact 

      Takahashi, Toru; Spicher, Andres; Di Mare, Francesca; Rowland, Douglas E.; Pfaff, Robert F.; Collier, Michael R.; Clausen, Lasse; Moen, Jøran Idar (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-16)
      The VISIONS-2 35.039 sounding rocket was launched from Ny-Ålesund, Svalbard, on 7 December 2018 at 11:06 UT, and traveled overhead of the cusp aurora. The payload reached an apogee of 806.6 km and provided measurements of the electric field (E) and electron density (N<sub>e</sub> ) with a high sampling rate of 6,250 Hz. The high-sampling-data make it possible to estimate the horizontal structure ...
    • Turbulence and Intermittency in the Winter Cusp Ionosphere Studied With the ICI Sounding Rockets 

      Di Mare, Francesca; Spicher, Andres; Clausen, Lasse; Miloch, Wojciech Jacek; Moen, Jøran Idar (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-15)
      The characteristics of turbulent plasma in the winter cusp ionosphere is studied based on in-situ data from the Investigation of Cusp Irregularities (ICI) sounding rockets. The electron density fluctuations from ICI-2 and ICI-3 missions have been analyzed for the whole flight, using advanced timeseries analysis techniques. The analysis of the autocorrelation scale is indicative of the turbulence ...