Technique for treating discrete received power in radio measurements from the RAD1 receiver on board WIND

The radio instruments within the WIND WAVES suite are widely used to observe terrestrial radio emissions, such as Auroral Kilometric Radiation (AKR), and solar radio bursts. However, instruments like radio receiver band 1 (RAD1) cannot observe multiple frequency channels simultaneously. Common observational modes sweep only a subset of available channels, and even full sweeps leave gaps between channels, resulting in ≈255 kHz of unsampled frequency space. Consequently, visualising and analysing received power as a continuous function of time and frequency requires methods to address these gaps.

We present a simple approach that reconstructs missing frequency information by exploiting the instrument’s native sampling cadence (≈ 3 s). Previous studies typically average the received power over a full frequency sweep (≈ 183 s), whereas our method retains variability on timescales constrained by the minimum interval between successive observations of the same frequency channel (≈ 44 s).

We apply this method to one solar Type III radio burst and two AKR events, comparing results with traditional approaches. Our method suggests previously unresolved substructures in AKR, consistent with a potentially bursty extension of the source region along magnetic field lines, and enables clearer separation of partially overlapping solar radio bursts. Integrated power analysis across selected frequency ranges indicates increased temporal variability and improved peak timing, demonstrating the method’s advantages beyond visualisation.