With the ultimate aim of using the fundamental or f -mode to study helioseismic aspects of turbulence-generated magnetic flux concentrations , we use randomly forced hydromagnetic simulations of a piecewise isothermal layer in two dimensions with reflecting boundaries at top and bottom .
We compute numerically diagnostic wavenumber–frequency diagrams of the vertical velocity at the interface between the denser gas below and the less dense gas above .
For an Alfvén-to-sound speed ratio of about 0.1 , a 5 % frequency increase of the f -mode can be measured when k _ { x } H _ { p } = 3 – 4 , where k _ { x } is the horizontal wavenumber and H _ { p } is the pressure scale height at the surface .
Since the solar radius is about 2000 times larger than H _ { p } , the corresponding spherical harmonic degree would be 6000–8000 .
For weaker fields , a k _ { x } -dependent frequency decrease by the turbulent motions becomes dominant .
For vertical magnetic fields , the frequency is enhanced for k _ { x } H _ { p } \approx 4 , but decreased relative to its nonmagnetic value for k _ { x } H _ { p } \approx 9 .