Transmission and conversion of magneto-acoustic waves in the quiet solar chromosphere
Abstract
We investigate the interaction between acoustic oscillations and the fine-scale structures found at the chromospheric network boundaries that form the magnetic canopy. To this end, high precision photospheric magnetograms obtained by SOT/SP on-board the Hinode space mission and time series of high spatial-resolution filtergrams in five wavelengths along the Hα line profile taken by the Dutch Open Telescope are utilized. We extrapolate the photospheric magnetic field using the current-free assumption to calculate the vector of the magnetic field and reconstruct the magnetic configuration of the chromosphere. Assuming the VAL-C atmospheric model we calculate the height of the magnetic canopy. Through wavelet analysis on the Hα observations we obtain the 2-D distribution of the oscillatory power at different atmospheric heights. We then compare the obtained distribution of power with the one predicted by a 2-D theoretical model at various magnetic field inclination angles. Our results show that the magnetic shadow and power halo phenomena observed in network regions may be attributed to the conversion/transmission of magneto-acoustic waves in the magnetic canopy. The amount of transmission/conversion depends on the frequency of the waves and the "attack" angle, i.e. the angle between the wave vector and magnetic field direction. This mechanism allows transmitted waves to propagate to greater atmospheric heights.
- Publication:
-
11th Hellenic Astronomical Conference
- Pub Date:
- September 2013
- Bibcode:
- 2013hell.conf....6K