  The radiative and jet power in active galactic nuclei is generated by
accretion of material on to supermassive galactic-centre black holes. For
quasars, where the radiative power is by definition very high, objects with
high radio luminosities form around 10 per cent of the population, although it
is not clear whether this is a stable phase. Traditionally, quasars with high
radio luminosities have been thought to present jets with edge-brightened
morphology (Fanaroff-Riley II - FR II) due to the limitations of previous radio
surveys (i.e., FRIs were not observed as part of the quasar population). The
LOw Frequency ARray (LOFAR) Two-metre Sky Survey (LoTSS) with its unprecedented
sensitivity and resolution covering wide sky areas has enabled the first
systematic selection and investigation of quasars with core-brightened
morphology (Fanaroff-Riley I - FR). We carried out a Very Large Array (VLA)
snapshot survey to reveal inner structures of jets in selected quasar
candidates; 15 (25 per cent) out of 60 sources show clear inner jet structures
that are diagnostic of FRI jets and 13 quasars (around 22 per cent) show
extended structures similar to those of FRI jets. Black hole masses and
Eddington ratios do not show a clear difference between FRI and FRII quasars.
FRII quasars tend to have higher jet powers than FRI quasars. Our results show
that the occurrence of FRI jets in powerful radiatively efficient systems is
not common, probably mainly due to two factors: galaxy environment and jet
power.
