• Millstone Hill ISR Measurements of Small Aspect Angle Spectra 

      Longley, William; Erickson, Philip J.; Vierinen, Juha; Oppenheim, Meers; Lind, Frank David; Dimant, Yakov (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-04)
      The Millstone Hill incoherent scatter (IS) radar is used to measure spectra close to perpendicular to the Earth's magnetic field, and the data are fit to three different forward models to estimate ionospheric temperatures. IS spectra measured close to perpendicular to the magnetic field are heavily influenced by Coulomb collisions, and the temperature estimates are sensitive to the collision operator ...
    • Solved and unsolved riddles about low-latitude daytime valley region plasma waves and 150-km echoes 

      Chau, Jorge Luis; Longley, William; Reyes, Pablo; Pedatella, Nick; Otsuka, Yuichi; Stolle, Claudia; Liu, Huixin; Vierinen, Juha; Milla, Marco; Hysell, David L.; Oppenheim, Meers; Patra, A.; Lehmacher, G; Kudeki, Erhan (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-27)
      The Earth’s atmosphere near both the geographic and magnetic equators and at altitudes between 120 and 200 km is called the low-latitude valley region (LLVR) and is among the least understood regions of the ionosphere/thermosphere due to its complex interplay of neutral dynamics, electrodynamics, and photochemistry. Radar studies of the region have revealed puzzling daytime echoes scattered from ...