What mechanisms allow 5-minute oscillations in active regions of the solar surface to penetrate from the photosphere into the chromosphere?

摘要

Some properties of the propagation of 5-minute oscillations from the bottom of the photosphere (h = 0 km) to the bottom of the chromosphere (h = 1600 km) are investigated based on the results of filter (at the center of the line Ca II lambda 396.8 nm), spectral (in the line Ba II lambda 455.4 nm), and spectropolarimetric (in the lines Fe I lambda lambda 1564.3-1565.8 nm) observations of the active region (isolated faculae at the center of the solar disk) on the German vacuum tower telescope (VTT) of the Institute of Astrophysics of the Canary Islands. Oscillations in the lower photosphere, in the transition region, and in the middle chromosphere reach their maximum during the period close to P a parts per thousand 5 min. At the height h = 1600 km, another period of oscillations P a parts per thousand 700 s can be seen well. Two factors facilitate the penetration of 5-minute oscillations from the photosphere into the chromosphere: the inclination of magnetic field lines and the deviation of the wave propagation process from the adiabatic one. The maximum power of 5-minute oscillations at the height h = 1600 km falls on inclination angles of the magnetic field in the range of 11A degrees aEuro"13A degrees and on the phase shift between oscillations of temperature and velocity of 40A degrees aEuro"50A degrees.