Blar i forfatter "Coster, Anthea"

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    • Conjugate ionospheric perturbation during the 2017 solar eclipse 

      Zhang, Shunrong; Erickson, Philip J.; Vierinen, Juha; Aa, Ercha; Rideout, William; Coster, Anthea; Goncharenko, Larisa (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-16)
      We report new findings of total electron content (TEC) perturbations in the southern hemisphere at conjugate locations to the northern eclipse on August 21, 2017. We identified a persistent conjugate TEC depletion by 10%–15% during the eclipse time, elongating along magnetic latitudes with at least ∼5° latitudinal width. As the Moon's shadow swept southward, this conjugate depletion moved northward ...

    • Ionospheric bow waves and perturbations induced by the 21 August 2017 solar eclipse 

      Zhang, Shun-Rong; Erickson, Philip j.; Goncharenko, Larisa; Coster, Anthea; Rideout, William; Vierinen, Juha (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-04)
      During solar eclipses, the Moon's shadow causes a large reduction in atmospheric energy input, including not only the stratosphere but also the thermosphere and ionosphere. The eclipse shadow has a supersonic motion which is theoretically expected to generate atmospheric bow waves, similar to a fast‐moving river boat, with waves starting in the lower atmosphere and propagating into the ionosphere. ...

    • Radio occultation observations of the solar corona over 1.60-1.86R⊙: Faraday rotation and frequency-shift analysis 

      Wexler, David; Hollweg, Joseph V; Efimov, Anatoli I; Song, Paul; Jensen, Elizabeth T; Lionello, Roberto; Vierinen, Juha; Coster, Anthea (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-09-02)
      The study of coronal energy transport, central to the solar wind acceleration problem, relies upon accurate representation of magnetic fields and plasma electron densities. This information is difficult to obtain in middle‐to‐lower coronal regions that may contain complex magnetic structures. Faraday rotation (FR) solar radio occultation observations, which reveal line‐of‐sight (LOS) integrated ...

    • Spacecraft Radio Frequency Fluctuations in the Solar Corona: A MESSENGER–HELIOS Composite Study 

      Wexler, David; Hollweg, J. V.; Efimov, A. I.; Lukanina, L. A.; Coster, Anthea; Vierinen, Juha; Jensen, E. A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-31)
      Fluctuations in plasma electron density may play a role in solar coronal energy transport and the dissipation of wave energy. Transcoronal spacecraft radio sounding observations reveal frequency fluctuations (FFs) that encode the electron number density disturbances, allowing an exploration of the coronal compressive wave and advected inhomogeneity models. Primary FF observations from MESSENGER 2009 ...

    • Subauroral and polar traveling ionospheric disturbances during 7-9 September 2017 storms 

      Zhang, Shunrong; Erickson, Philip j.; Coster, Anthea; Rideout, William; Vierinen, Juha; Jonah, Olusegun; Goncharenko, Larisa (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-12-25)
      This study provides new scenarios for storm time traveling ionospheric disturbance excitation and subsequent propagation at subauroral and polar latitudes. We used ground‐based total electron content observations from Global Navigation Satellite System receivers combined with wide field, subauroral ionospheric plasma parameters measured with the Millstone Hill Incoherent Scatter Radar during strong ...

    • Traveling ionospheric disturbances and ionospheric perturbations associated with solar flares in September 2017 

      Zhang, Shun-Rong; Coster, Anthea; Erickson, Philip j.; Goncharenko, Larisa; Rideout, William; Vierinen, Juha (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-10)
      Solar flares provide strong impulsive radiation and energy injection to the sunlit upper atmosphere. The impact on the ionosphere is immense in spatial scale, and therefore, it is not immediately evident if dramatically elevated neutral heating can lead to excitation of acoustic gravity waves. Using primary observations from Global Navigation Satellite System differential TEC (total electron ...