A measurement of small-scale features using ionospheric scintillation. Comparison with refractive shift measurements

We present a study of scintillation induced by the mid-latitude ionosphere. By implementing methods currently used in Interplanetary Scintillation studies to measure amplitude at low frequencies, we have proven it is possible use Murchison Widefield Array ionospheric weak regime, which sensitive structures on scales $\sim$300 m our observing frequency 154 MHz, where phase variance this scale was 0.06 rad$^{2}$ most extreme case observed. Analysing over 1000 individual 2-minute observations, compared with that inferred previous measurements refractive shifts, are almost an order magnitude larger. The two were found be highly correlated (Pearson correlation coefficient 0.71). observed for active ionosphere, relationship between these metrics line what would expected if ionosphere's structure described Kolmogorov turbulence relevant 300m and 2000m. In conditions, shifts sometimes underestimate small-scale factor four or more, conditions could significant effects radio astronomy observations.