Do magnetic fields modify tidal dissipation in the convective envelope of low-mass stars along their evolution?

International audience; The dissipation of the kinetic energy of large-scale and wave-like tidal flows within the convective envelope of low-mass stars is one of the key physical mechanisms that shape the orbital and rotational dynamics of short-period exoplanetary systems. In the case of stable binary systems, they lead to the orbit circularisation and to the spins synchronisation and alignment; in the case of unstable systems they drive the spiraling of the planet towards the central star. In addition, stellar convective envelopes are (differentially) rotating, turbulent, and magnetized regions where an active dynamo action is sustained (e.g. Brun & Browning 2017 and references therein). Therefore, as demonstrated by first theoretical works and numerical simulations, tidal flows and waves excitation, propagation, and dissipation can be impacted by stellar magnetic fields (e.g. Wei 2017, Lin & Ogilvie 2018, Wei 2018). For instance, the so-called dynamical tide is constituted of magneto-inertial waves (their restoring forces being the Lorentz force and the Coriolis acceleration) instead of inertial waves in the non-magnetized case. In the meanwhile, the amplitude and the geometry of dynamo-generated magnetic fields vary along the evolution of low-mass stars (e.g. Vidotto et al. 2014, Brun & Browning 2017 and references therein). In this framework, the key question that should be answered is "for which stellar masses, rotation and evolution phases, do we need to take into account the action of magnetic fields on tidal waves excitation, propagation, and dissipation?". In this work, we identify the terms in MHD equations that should be computed to evaluate the impact of magnetic fields on tidal dissipation in the convective envelope of active rotating low-mass stars hosting planets. Using scaling laws that provide the amplitude of dynamo-generated magnetic fields along the structural and rotational evolution of these stars (e.g. Augustson, Mathis & Brun 2016) combined with detailed grids of rotating stellar models (e.g. Amard et al. 2016), we demonstrate that a full MHD treatment of tidal waves excitation, propagation, and dissipation is required for all low-mass stars (from M to F-type stars) all along their evolution. Consequences for the dynamical evolution of short-period exoplanetary systems are finally discussed.