Related papers: A model of a tidally synchronized solar dynamo
In this paper we extend the previous work of Papaloizou \& Savonije on tidal interactions between a solar mass star and a closely orbiting giant planet which is such that the orbital and stellar spin angular momentum directions are…
Stellar oscillations are excited in non-synchronously rotating stars in binary systems due to the tidal forces. Tangential components of the tides can drive a shear flow which behaves as a differentially forced rotating structure in a…
The frequency spectrum of the hemispheric asymmetry of solar activity shows enhanced power for the period ranges around 8.5 years and between 30 and 50 years. This can be understood as the sum and beat periods of the superposition of two…
The solar magnetic activity cycle has an amplitude that varies within a wide but limited range of values. This implies that there are nonlinear mechanisms that prevent runaway solutions. The purpose of this paper is to propose observable…
The leading theoretical paradigm for the Sun's magnetic cycle is an $\alpha\omega$-dynamo process, in which a combination of differential rotation and turbulent, helical flows produces a large-scale magnetic field that reverses every 11…
One possible scenario for the origin of the solar tachocline, known as the "fast tachocline", assumes that the turbulent diffusivity exceeds eta>10^9 cm^2/s. In this case the dynamics will be governed by the dynamo-generated oscillatory…
Surface differential rotation (SDR) plays a key role in dynamo models. SDR estimates are therefore essential for constraining theoretical models. We measure a lower limit to SDR in a sample of solar-like stars belonging to young…
The Sun is a magnetic star whose magnetism and cyclic activity is linked to the existence of an internal dynamo. We aim to understand the establishment of the solar magnetic 22-yr cycle, its associated butterfly diagram and field parity…
The fluid dynamics in planet Saturn gives rise to alternating east-west jet streams, large cyclonic and anticyclonic vortices, and a dipole-dominant magnetic field which is highly axisymmetric about the planetary rotation axis. Modelling…
Among planetary dynamos, the magnetic field of Saturn stands out in its exceptional level of axisymmetry. One of its peculiar features is that the magnetic dipole mode is tilted with respect to the planetary rotation axis by only $\approx…
Observations of long-term north-south asymmetry in solar activity demand the equator-symmetric (quadrupolar) mode be present in the solar magnetic field in line with the dominant antisymmetric (dipolar) mode. This paper proposes treating…
Observations in polarized emission reveal the existence of large-scale coherent magnetic fields in a wide range of spiral galaxies. Radio-polarization data show that these fields are strongly inclined towards the radial direction, with…
Numerical simulations that reproduce solar-like magnetic cycles can be used to generate long-term statistics. The variations in N-S hemispheric cycle synchronicity and amplitude produced in simulations has not been widely compared to…
The level of solar magnetic activity, as exemplified by the number of sunspots and by energetic events in the corona, varies on a wide range of time scales. Most prominent is the 11-year solar cycle, which is significantly modulated on…
We calculate the dynamical tides raised on a non-rotating solar-type star by a close stellar or planetary companion. Dissipation arising from a turbulent viscosity operating in the convection zone and radiative damping in the radiative core…
Tidal torques can alter the spins of tidally interacting stars and planets, usually over shorter timescales than the tidal damping of orbital separations or eccentricities. Simple tidal models predict that, in eccentric binary or planetary…
The tidal interactions of planets affect the stellar evolutionary status and the constraint of their physical parameters by gyrochronology. In this work, we incorporate the tidal interaction and magnetic braking of the stellar wind into…
We extend the study of Papaloizou & Savonije of the tidal interactions of close orbiting giant planets with a central solar type star to the situation where the spin axis of the central star and the orbital angular momentum are misaligned.…
We use the mean-field dynamo equations to show that an incoherent alpha effect in mirror-symmetric turbulence in a shearing flow can generate a large scale, coherent magnetic field. We illustrate this effect with simulations of a few simple…
Recent analyses of helioseismological observations seem to suggest the presence of two new phenomena connected with the dynamics of the solar convective zone. Firstly, there are present torsional oscillations with periods of about 11 years,…