Simultaneous observations of irregular sporadic E structures using the LWA and a DPS4D

Multi-instrument studies have recently shed new light on the morphology of sporadic E, especially intense sporadic E. Here we present simultaneous observations of dense sporadic E ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m1"><mml:mrow><mml:msub><mml:mrow><mml:mtext>E</mml:mtext></mml:mrow><mml:mrow><mml:mi>s</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math> ) 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 located over 500 km away in Texas. The LWA appears to be most sensitive to the densest E s structures, which also appear to contain irregularities with vertical structure, possibly indicating turbulence. These irregularities cause off-zenith backscatter, as observed by the DPS4D, and are observed to move at speeds of a few tens of m/s. The irregularities also appear to act as a phase screen, producing short-lived daytime spread F and E conditions. We hypothesize that turbulent structures driven by the Kelvin–Helmholtz (KH) instability may be responsible for the observations.