Blar i forfatter "Marholm, Sigvald"

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    • Electron-neutral collisions effects on Langmuir probe in the lower E-region ionosphere 

      Brask, Steffen Mattias; Marholm, Sigvald; Di Mare, Francesca; Adhikari, Sayan; Spicher, Andres; Takahashi, T.; Miloch, Wojciech Jacek (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-21)
      We present the first set of particle-in-cell simulations including Monte Carlo collisions between charged and neutral particles used to simulate a cylindrical Langmuir probe in the electron saturation regime with a collisional electron sheath. We use a setup focused on the E-region ionosphere; however, the results of these simulations are analyzed in a general sense using dimensionless values. We ...

    • The role of particle precipitation on plasma structuring at different altitudes by in-situ measurements 

      Buschmann, Lisa Marie; Bonnell, John W.; Bounds, Scott; Clausen, Lasse; Kletzing, Craig; Marholm, Sigvald; Miloch, Wojciech Jacek; Roglans, Roger; Spicher, Andres (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-06-02)
      The plasma in the cusp ionosphere is subject to particle precipitation, which is important for the development of large-scale irregularities in the plasma density. These irregularities can be broken down into smaller scales which have been linked to strong scintillations in the Global Navigation Satellite System (GNSS) signals. We present power spectra for the plasma density irregularities in the ...

    • Wake formation behind Langmuir probes in ionospheric plasmas 

      Jao, Chun-Sung; Marholm, Sigvald; Spicher, Andres; Miloch, Wojciech Jacek (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-20)
      This paper presents a simulation study of the wake formation behind a Langmuir probe thinner than the Debye Length in the space environments such as the ionosphere’s F region. We find that the wakes formed in plasma density and electric potential behind the positively biased probe can extend up to 15 Debye lengths in the subsonic plasma flow. Higher electric bias and flow velocity can further enhance ...