• Extreme Event Statistics in Dst, SYM-H, and SMR Geomagnetic Indices 

      Bergin, A.; Chapman, Sandra; Watkins, N.W.; Moloney, N.R.; Gjerløv, Jesper (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-20)
      Extreme space weather events are rare, and quantifying their likelihood is challenging, often relying on geomagnetic indices obtained from ground-based magnetometer observations that span multiple solar cycles. The Dst index ring-current monitor, derived from an hourly average over four low-latitude stations, is a benchmark for extreme space weather events, and has been extensively studied ...
    • Network analysis of geomagnetic substorms using the SuperMAG database of ground-based magnetometer stations 

      Dods, Joe; Chapman, Sandra; Gjerløv, Jesper (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-09-26)
      The overall morphology and dynamics of magnetospheric substorms is well established in terms of the observed qualitative auroral features seen in ground-based magnetometers. This paper focuses on the quantitative characterization of substorm dynamics captured by ground-based magnetometer stations. We present the first analysis of substorms using dynamical networks obtained from the full available ...
    • Solar illumination dependence of the auroral electrojet intensity: Interplay between the solar zenith angle and dipole tilt 

      Ohtani, Shinici; Gjerløv, Jesper; Johnsen, Magnar Gullikstad; Yamauchi, Masatoshi; Brändström, Urban; Lewis, Andrew M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-18)
      The present study investigates the dependence of the local auroral electrojet (AEJ) intensity on solar illumination by statistically examining northward geomagnetic disturbances in the auroral zone in terms of the solar zenith angle χ. It is found that on the dayside, both westward and eastward electrojets (WEJ and EEJ) are more intense for smaller χ, suggesting that the solar extreme ultraviolet‐induced ...