Simultaneous Observations of Irregular Sporadic E Structures with the LWA and a DPS4D

Kenneth S. Obenberger ^1* C A Taylor ² J Colman ¹ E Dao ¹ J Dowell ² J V Eccles ³ D J Emmons ⁴ C T Fallen ⁵ J M Holmes ¹ G B Taylor ²

• ¹ Space Vehicles Directorate, Air Force Research Laboratory, Albuquerque, United States
• ² University of New Mexico, Albuquerque, New Mexico, United States
• ³ Space Dynamics Laboratory, Utah State University, Logan, Utah, United States
• ⁴ Air Force Institute of Technology, Wright-Patterson AFB, Ohio, United States
• ⁵ Fourth State Communications, LLC, Cheyenne, Wyoming, United States

We present simultaneous observations of dense sporadic E (E s ) structures using the Long Wavelength Array (LWA) radio telescopes and a Digisonde Portable Sounder 4D (DPS4D). Our coordinated observations show that the LWA radio telescopes in central New Mexico can reliably locate regions of dense Es structures as they pass over a Digisonde over 500 km away in Texas.The LWA is most sensitive to the densest E s structures which also appear to contain irregularities with vertical structure, possibly turbulent. These irregularities cause off-zenith backscatter as seen by the DPS4D and are observed to move at speeds of a few 10s of m/s. The irregularities also appear to act as a phase screen, producing short-lived daytime spread F as well as spread E conditions. We hypothesize that turbulent structures driven by the Kelvin Helmholtz instability may be responsible for the observations.