相关论文: Stellar Differential Rotation and Coronal Timescal…
Despite progress in the observations of stellar magnetic fields, their physical mechanisms remain poorly understood. During the pre-main sequence (PMS) phase, the inner layers of stars contract and a radiative core gradually develops. In…
(abridged) Context: Solar-like differential rotation is characterized by a rapidly rotating equator and slower poles. However, theoretical models and numerical simulations can result in a slower equator and faster poles when the rotation is…
We study an evolving bipolar active region that exhibits flux cancellation at the internal polarity inversion line, the formation of a soft X-ray sigmoid along the inversion line and a coronal mass ejection. The evolution of the…
Using observations from the SOHO, STEREO and Hinode, we investigate magnetic field evolution in an equatorial coronal hole region. Two dipoles emerge one by one. The negative element of the first dipole disappears due to the interaction…
Rotation has a number of important effects on the evolution of stars. It decreases the surface gravity, causes enhanced mass loss and leads to surface abundance anomalies of various chemical isotopes. We have adapted the Cambridge stellar…
Gyrochronology and recent theoretical findings are used to reduce the number of input parameters of differential rotation models. This eventually leads to a theoretical prediction for the surface differential rotation as a function of only…
Sun-like stars shed angular momentum due to the presence of magnetised stellar winds. Magnetohydrodynamic models have been successful in exploring the dependence of this "wind-braking torque" on various stellar properties, however the…
We have computed new stellar evolution models that include the effects of rotation and magnetic torques under different hypothesis. The goal is to test if a single star can sustain in the envelope the rotational velocities needed for the…
In the solar convection zone, rotation couples with intensely turbulent convection to build global-scale flows of differential rotation and meridional circulation. Our sun must have rotated more rapidly in its past, as is suggested by…
We investigate the change in stellar magnetic topology across the fully-convective boundary and its effects on coronal properties. We consider both the magnitude of the open flux that influences angular momentum loss in the stellar wind and…
As a massive star evolves through multiple stages of nuclear burning on its way to becoming a supernova, a complex, differentially rotating structure is set up. Angular momentum is transported by a variety of classic instabilities, and also…
The daily measurements of the disc-integrated solar radio flux, observed by the Radio Solar Telescope Network (RSTN), at 245, 410, 610, 1415, 2695, 4995, and 8800 MHz during the time interval of 1989 January 1 to 2019 December 17, are used…
Our understanding of the structure and dynamics of stellar coronae has changed dramatically with the availability of surface maps of both star spots and also magnetic field vectors. Magnetic field extrapolations from these surface maps…
We examine the generation of a magnetic field in a solar-like star and its effects on the internal distribution of the angular velocity. We suggest that the evolution of a rotating star with magnetic fields leads to an equilibrium value of…
The most probable initial magnetic configuration of a CME is a flux rope consisting of twisted field lines which fill the whole volume of a dark coronal cavity. The flux ropes can be in stable equilibrium in the coronal magnetic field for…
Using a non-linear Monte-Carlo code we investigate the radiative response of an accretion disk corona system to static homogeneous flares. We model a flare by a rapid (comparable to the light crossing time) energy dissipation in the corona…
Observations of chromospheric and coronal emissions from various solar-type stars show that the stellar magnetic activity varies with the rotation rates of the stars. The faster the star rotates, its magnetic activity gets stronger but…
We discuss the evolution of solar coronal element abundances over an active region lifetime. Magneto-convection drives the complexity of magnetic fields that emerge above the photosphere. This complexity is dissipated, together with that of…
The magnetic fields of solar-type stars are observed to cycle over decadal periods -11 years in the case of the Sun. The fields originate in the turbulent convective layers of stars and have a complex dependency upon stellar rotation rate.…
Magnetic flux ropes (MFRs) are fundamental magnetic structures in solar eruptions, whose formation is generally attributed to (1) the emergence of subsurface flux tubes or (2) flux cancellation driven by photospheric horizontal flows and…