Speaker
Description
Radio waves that travel though the ionosphere experience a deformation in their wavefronts. Those perturbation are
caused by inhomogeneities in the spatial distribution of the refractive index. The received signal is affected by temporal
fluctuations in its phase and intensity.
Ionospheric disturbances are present in received signal with frequencies between the VHF and C band. In particular,
intensity scintillation is visible when the signal travels through plasma density irregularities with small spatial scales.
Ionosphere conditions are observed and studied with use of the Global Navigation Satellite Systems (GNSS), where
ground-based receivers observe the radio signals coming from the satellites. Moreover, the radio telescopes (such as
LOFAR – LOw Frequency ARray) are being increasingly utilised for ionospheric studies in recent years. Such multi-
instrumental approach has a significant impact on the field of ionospheric studies and is expected to bring new insight
ine ionospheric plasma dynamics as well as in ionospheric radio wave propagation. The mutual observations with
GNSS and LOFAR can be utilised to determine the properties of the ionosphere irregularities as it has not been done
before.
Ionosphere scintillation can be quantified by means the S 4 intensity scintillation index (the standard deviation of the
normalized signal intensity). The S 4 index is attributable to ionospheric irregularities in the inertial sub-range where
electron density irregularities can induce scintillation.
Ionospheric propagation effects have an impact on other observations, such as from pulsars. The combination of
ionospheric observations from different instruments such as LOFAR and GNSS helps describe the properties of
ionospheric irregularities and their propagation effects in a way that has not been done before. This contribution
discusses the interpretation of ionospheric observations measured, for example, by means of LOFAR and GNSS.
