Blar i forfatter "Kwak, Young-Sil"

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    • EISCAT Observation of Wave‐Like Fluctuations in Vertical Velocity of Polar Mesospheric Summer Echoes Associated With a Geomagnetic Disturbance 

      Lee, Young-Sook; Kim, Young Ha; Kim, Kyung-Chan; Kwak, Young-Sil; Sergiengko, Timothy; Kirkwood, Sheila; Johnsen, Magnar Gullikstad (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-04)
      By analyzing a data set from the European Incoherent SCATter (EISCAT) Very High Frequency (VHF) radar at Tromsø, we find that both radar reflectivity and upward ion velocity in a polar mesospheric summer echo (PMSE) layer simultaneously increased at the commencement of a local geomagnetic disturbance, which occurred at midnight on 9 July 2013. The onset of the upward velocity was followed by periodic ...

    • Steepening Plasma Density Spectra in the Ionosphere: The Crucial Role Played by a Strong E-Region 

      Ivarsen, Magnus Fagernes; St-Maurice, Jean-Pierre; Jin, Yaqi; Park, Jaeheung; Miloch, Wojciech Jacek; Spicher, Andres; Kwak, Young-Sil; Clausen, Lasse B. N. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-28)
      Based on the Swarm 16 Hz Advanced Plasma Density data set, and using the Swarm A satellite, we apply automatic detection of spectral breaks in seven million sampled plasma density power spectra in the high-latitude F-region ionosphere. This way, we survey the presence of plasma irregularity dissipation due to an enhanced E-region conductance, caused both by solar photoionization and particle ...