Crynodeb
Solar fundamental (f) acoustic mode oscillations are investigated analytically in a magnetohydrodynamic (MHD) model. The model consists of three layers in planar geometry, representing the solar interior, the magnetic atmosphere, and a transitional layer sandwiched between them. Since we focus on the fundamental mode here, we assume the plasma is incompressible. A horizontal, canopylike, magnetic field is introduced to the atmosphere, in which degenerated slow MHD waves can exist. The global (fmode) oscillations can couple to local atmospheric Alfvén waves, resulting, e.g., in a frequency shift of the oscillations. The dispersion relation of theglobal oscillation mode is derived, and is solved analytically for the thintransitional layer approximation and for the weakfield approximation. Analytical formulae are also provided for the frequency shifts due to the presence of a thin transitional layer and a weak atmospheric magnetic field. The analytical results generally indicate that, compared to the fundamental value (ω=gk), the mode frequency is reduced by the presence of an atmosphere by a few per cent. A thin transitional layer reduces the eigenfrequencies further by about an additional hundred microhertz. Finally, a weak atmospheric magnetic field can slightly, by a few percent, increase the frequency of the eigenmode. Stronger magnetic fields, however, can increase the fmode frequency by even up to ten per cent, which cannot be seen in observed data. The presence of a magnetic atmosphere in the threelayer model also introduces nonpermitted propagation windows in the frequency spectrum; here, fmode oscillations cannot exist with certain values of the harmonic degree. The eigenfrequencies can be sensitive to the background physical parameters, such as an atmospheric density scaleheight or the rate of the plasma density drop at the photosphere. Such information, if ever observed with highresolution instrumentation and inverted, could help to gain further insight into solar magnetic structures by means of solar magnetoseismology, and could provide further insight into the role of magnetism in solar oscillations
Iaith wreiddiol  Saesneg 

Tudalennau (oi)  759776 
Nifer y tudalennau  18 
Cyfnodolyn  Advances in Space Research 
Cyfrol  61 
Rhif cyhoeddi  2 
Dyddiad arlein cynnar  22 Tach 2017 
Dynodwyr Gwrthrych Digidol (DOIs)  
Statws  Cyhoeddwyd  15 Ion 2018 
Ôl bys
Gweld gwybodaeth am bynciau ymchwil 'Fundamental (f) Oscillations in a Magnetically Coupled Solar InteriorAtmosphere System: An Analytical Approach'. Gyda’i gilydd, maen nhw’n ffurfio ôl bys unigryw.Proffiliau

Balazs Pinter
 Cyfadran Busnes a’r Gwyddorau Ffisegol, Ffiseg  Senior Lecturer
Unigolyn: Dysgu ac Ymchwil