Resonant Conversion of Standing Acoustic Oscillations into Alfvén Waves in the Β∼1 Region of the Solar Atmosphere
نویسندگان
چکیده
We show that 5-minute acoustic oscillations may resonantly convert into Alfvén waves in the β∼1 region of the solar atmosphere. Considering the 5-minute oscillations as pumping standing acoustic waves oscillating along unperturbed vertical magnetic field, we find on solving the ideal MHD equations that amplitudes of Alfvén waves with twice the period and wavelength of acoustic waves exponentially grow in time when the sound and Alfvén speeds are equal, i.e. cs ≈ vA. The region of the solar atmosphere where this equality takes place we call a swing layer. The amplified Alfvén waves may easily pass through the chromosphere and transition region carrying the energy of p-modes into the corona.
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