Speaker
Description
LOFAR (LOw Frequency ARray) radio telescope network enables high-resolution interferometric observations in the frequency range of 10 – 240 MHz. It can be used as a distributed array, but utilising a single LOFAR station can also provide valuable information. The cross-correlation data enable sky imaging at selected frequencies, with a time resolution of 1 second. Such mapping can be used for monitoring the apparent position of the strongest radio sources over time.
The position variability at low radio frequencies depends on the ionospheric conditions. Total Electron Content (TEC) along the line of sight, especially horizontal gradients in TEC, can impact systematic shifts in the apparent radio source position. The temporal evolution of its shift can be used to observe the structures in the ionosphere.
The LOFAR PL610 station in Borówiec, Poland, was used to conduct continuous observations of the strongest group of radio sources (the A-Team: CasA, CygA, TauA, and VirA) for over two years. The available data are recorded in local time, allowing monitoring of diurnal ionospheric variability, as well as observations of space weather events.
In the following study, we present the standard patterns related to the diurnal ionospheric cycle, including build-up and decay of ionospheric gradients during the day. Moreover, we show the ionospheric disturbances triggered by geomagnetic storms. The analysis provides insight into the dynamics of the ionosphere in the mid-latitude geomagnetic region, utilising the LOFAR PL610 station as a tool for monitoring the ionospheric region that cannot be monitored so efficiently with GNSS methods.
