Magnetic fingerprints of solar and stellar oscillations
نویسنده
چکیده
Waves connect all the layers of the Sun, from its interior to the upper atmosphere. It is becoming clear now the important role of magnetic field on the wave propagation. Magnetic field modifies propagation speed of waves, thus affecting the conclusions of helioseismological studies. It can change the direction of the wave propagation, help channeling them straight up to the corona, extending the dynamic and magnetic couplings between all the layers. Modern instruments provide measurements of complex patterns of oscillations in solar active regions and of tiny effects such as temporal oscillations of the magnetic field. The physics of oscillations in a variety of magnetic structures of the Sun is similar to that of pulsations of stars that posses strong magnetic fields, such as roAp stars. All these arguments point toward a need of systematic self-consistent modeling of waves in magnetic structures that is able to take into account the complexity of the magnetic field configurations. In this paper, we describe simulations of this kind, summarize our recent findings and bring together results from the theory and observations.
منابع مشابه
Study of Solar Magnetic and Gravitational Energies Through the Virial Theorem
Virial theorem is important for understanding stellar structures. It produces an interesting connection between magnetic and gravitational energies. Using the general form of the virial theorem including the magnetic field (toroidal magnetic field), we may explain the solar dynamo model in relation to variations of the magnetic and gravitational energies. We emphasize the role of the gravitatio...
متن کاملOscillations of a Giant Solar Tornado
Solar magnetic tornadoes are known to be one of the mass and energy transport mechanisms from the lower solar atmosphere into the upper layers of the solar corona. A bright spiral structure with two arms is observed using high-cadence EUV images of 171, 193 and 304 Ǻ channels of Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory (SDO) on 10th of July 2011 for three hours. ...
متن کاملStellar magnetic activity and variability of oscillation parameters — An investigation of 24 solar - like stars observed by Kepler
Context. The Sun and solar-like stars undergo activity cycles for which the underlying mechanisms are not well understood. The oscillations of the Sun are known to vary with its activity cycle and these changes provide diagnostics on the conditions below the photosphere. Kepler has detected oscillations in hundreds of solar-like stars but as of yet, no widespread detection of signatures of magn...
متن کاملپایش خودکار حلقه های تاج خورشید و آشکارسازی نوسانات آنها
Identification and tracking of solar coronal loops is key to understanding solar magnetic field. Slow and fast Magnetohydrodynamic oscillation of tracked loops from sequence 171Å extreme ultra – violet images was detected. The method was demonstrated using 171Å images taken by SDO/AIA on 14 August 2010 and 20 January 2012. Two dimensional continuous wavelet transform (CWT) was used to clarify ...
متن کاملChanneling 5-min photospheric oscillations into the solar outer atmosphere through small-scale vertical magnetic flux tubes
We report two-dimensional MHD simulations which demonstrate that photospheric 5-min oscillations can leak into the chromosphere inside small-scale vertical magnetic flux tubes. The results of our numerical experiments are compatible with those inferred from simultaneous spectropolarimetric observations of the photosphere and chromosphere obtained with the Tenerife Infrared Polarimeter (TIP) at ...
متن کامل