Related papers: Alfven Waves in Disks, Outflows and Jets
AIMS: We examine whether ejection phenomena from accreting T Tauri stars can be described by only one type of self-collimated jet model. METHODS: We present analytical kinematic predictions valid soon after the Alfv\'en surface for all…
The theory of jet emitting disks (JEDs) provides a mathematical framework for a self-consistent treatment of steady-state accretion and ejection. A large-scale vertical magnetic field threads the accretion disk where magnetic turbulence…
The birth of stars involves not only accretion but also, counter-intuitively, the expulsion of matter in the form of highly supersonic outflows. Although this phenomenon has been seen in young stars, a fundamental question is whether it…
We investigate the driving mechanism of Alfv\'en wave-driven stellar winds from red giant stars, Arcturus ($\alpha$ Boo; K1.5 III) and Aldebaran ($\alpha$ Tau; K5 III), with nonideal MHD simulations in 1D super-radially open flux tubes.…
Context. It is known that Alfv\'en and magnetoacoustic waves both contribute to the heating of the solar chromosphere and drive plasma outflows. In both cases, the thermalization of the wave energy occurs due to ion-neutral collisions, but…
We describe the presence of wavefront dislocations in magnetohydrodynamic waves in stratified stellar atmospheres. Scalar dislocations such as edges and vortices can appear in Alfv\'en waves, as well as in general magneto-acoustic waves. We…
The steady, supersonic outflow from the Sun we call the solar wind was first posited in the 1950s and initial theories rightly linked the acceleration of the wind to the existence of the million-degree solar corona. Still today, the wind…
There is observational evidence of the presence of small-amplitude transverse magnetohydrodynamic (MHD) waves with a wide range of frequencies in the threads of solar prominences. It is believed that the waves are driven at the photosphere…
Classical T Tauri stars (CTTS) exhibit strong variability over timescales of minutes to decades. However, much theoretical work assumes that CTTS are in stable spin states. Here, we test expectations for CTTS angular momentum regulation by…
Among the many intriguing aspects of optically discovered tidal disruption events (TDEs) is that their temperatures are lower than expected and that the temperature does not evolve as rapidly with decreasing fallback rate as would be…
As established by ground based surveys, white dwarfs with hydrogen atmospheres pulsate as they cool across the temperature range, $12500\,\mathrm{K} \gtrsim T_{\mathrm{eff}} \gtrsim 10800\,\mathrm{K}$. Known as DAVs or ZZ Ceti stars, their…
We investigate mass losses via stellar winds from sun-like main sequence stars with a wide range of activity levels. We perform forward-type magnetohydrodynamical numerical experiments for Alfven wave-driven stellar winds with a wide range…
Instabilities in a neutron star can generate Alfv\'en waves in its magnetosphere. Propagation along the curved magnetic field lines strongly shears the wave, boosting its electric current $j_{\rm A}$. We derive an analytic expression for…
Recent work suggests that inwardly propagating internal gravity waves (IGWs) within a star can be fully converted to outward magnetic waves (MWs) if they encounter a sufficiently strong magnetic field. The resulting magnetic waves dissipate…
Heating of magnetized turbulent plasma is calculated in the framework of Burgers turbulence [A.M. Polyakov, Phys. Rev. E. 52, 6183 (1995)]. Explicit formula for the energy flux of Alfven waves along the magnetic field is presented. The…
First evidences of IR excess and disk mass accretion (strong H$\alpha$ emission) around brown dwarfs seem to indicate the existence of circumstellar disks around these sub-stellar objects. Nothing is known at the present time about outflows…
This paper examines the outflows associated with the interaction of a stellar magnetosphere with an accretion disk. In particular, we investigate the magnetospheric ejections (MEs) due to the expansion and reconnection of the field lines…
We present an instability occurring in the inner part of disks threaded by a moderately strong vertical (poloidal) magnetic field. Its mechanism is such that a spiral density wave in the disk, driven by magnetic stresses (rather than…
An analysis of the Alfven wave generation associated with the barium vapor release at altitudes ~ 5.2 Earth's radii (ER) in the magnetosphere is presented. Such injections were executed in G-8 and G-10 experiments of the Combined Radiation…
Young low-mass stars are characterized by ejection of collimated outflows and by circumstellar disks which they interact with through accretion of mass. The accretion builds up the star to its final mass and is also believed to power the…