  Stellar magnetism plays an important role in stellar evolution theory.
Approximatively 10% of observed main sequence (MS) and pre-main-sequence (PMS)
radiative stars exhibit surface magnetic fields above the detection limit,
raising the question of their origin. These stars host outer radiative
envelopes, which are stably stratified. Therefore, they are assumed to be
motionless in standard models of stellar structure and evolution. We focus on
rapidly rotating, radiative stars which may be prone to the tidal instability,
due to an orbital companion. Using direct numerical simulations in a sphere, we
study the interplay between a stable stratification and the tidal instability,
and assess its dynamo capability. We show that the tidal instability is
triggered regardless of the strength of the stratification
(Brunt-V{\"a}is{\"a}l{\"a} frequency). Furthermore, the tidal instability can
lead to both mixing and self-induced magnetic fields in stably stratified
layers (provided that the Brunt-V{\"a}is{\"a}l{\"a} frequency does not exceed
the stellar spin rate in the simulations too much). The application to stars
suggests that the resulting magnetic fields could be observable at the stellar
surfaces. Indeed, we expect magnetic field strengths up to several
Gauss.Consequently, tidally driven dynamos should be considered as a
(complementary) dynamo mechanism, possibly operating in radiative MS and PMS
stars hosting orbital companions. In particular, tidally driven dynamos may
explain the observed magnetism of tidally deformed and rapidly rotating
Vega-like stars.
