The possibility of using all-sky meteor radar to study the spatial features of ionospheric plasma bubbles

The all-sky meteor radars are primarily designed for observations of mesospheric neutral wind. Recently, the capability of all-sky radars in investigating ionospheric irregularities of the Bragg scales has been developed. However, limited by the relatively small range gate span of the all-sky radar, this capability is mainly constrained to the observations of irregularities at lower altitudes, e.g., E-region irregularities. The F-region irregularities at higher altitudes up to hundreds of kilometers, e.g., equatorial plasma bubbles (EPBs), are usually considered beyond the detection range of all-sky radars. In this paper, we try to extend the capability of a conventional interferometric all-sky meteor radar located at Sanya (18.4°N, 109.7°E) for investigating the spatial features of EPBs. Based on the arriving angles of irregularity backscatter echoes obtained by the radar interferometry technique, and according to the magnetic sensitivity of the EPB field-aligned irregularities, the true ranges of the irregularity structures could be determined to further reveal the spatial features of EPB structures. The results are confirmed by the collocated narrow-beam very high frequency (VHF) radar and the Low lAtitude long Range Ionospheric raDar (LARID). It is revealed that the all-sky radar could be employed to investigate EPB irregularities in a larger zonal region than narrow-beam VHF radars, which could be up to ~2000 km. The observations could well cover the blind area of the LARID field-of-view, and thus could be employed to continuously trace EPB occurrences and evolutions over thousands of kilometers by combining with LARID in future studies.