Description
The LOw Frequency ARray (LOFAR) is a radio telescope centred in The Netherlands, with international stations spread as far as Ireland and Latvia. To provide accurate images of astronomical sources, distortions to the observed signal must be minimised, and a primary cause of distortions is spatial and temporal variability in the ionosphere. As a result, the calibration process for astronomical images produces extremely precise measurements of ionospheric conditions across the array.The main ionospheric measurement provided by the calibration is differential Total Electron Content (dTEC). This is the difference in TEC along one station’s line of sight to that of another (the reference station) over each integration interval. dTEC is determined to high precision (~1 mTECu) and at high time resolution (up to ~4 s). Using the high density of stations in The Netherlands (baselines ranging from ~100 m to ~50 km), these measurements can reveal ionospheric structures across a range of time and length scales with high sensitivity.
In order to identify waves, we use a continuous wavelet transform to quantify the amplitude and phase of any wave signal in the dTEC on each baseline as a function of period and time. For regions of this time-period space where wave activity is identified, the phases and amplitudes of the wavelet coefficients as a function of baseline are used to estimate the wavelength, propagation direction and amplitude of the wave. By estimating the noise background spectrum of the data, rigorous estimates of the uncertainty on these parameters are also obtained.
| Period | Apr 2023 |
|---|---|
| Event title | Magnetosphere Ionosphere and Solar-Terrestrial Physics (MIST) meeting |
| Event type | Conference |
| Location | Birmingham, United KingdomShow on map |
| Degree of Recognition | National |