Effects of weak-to-moderate vertical magnetic fields on solar f- and p-modes

Observations indicate that solar p-modes encountering regions of enhanced magnetic field such as active region plage are partially absorbed. We adopt a simple vertical field model and investigate the possiblity that the responsible mechanism is slow mode leakage, which has been at least partially successful in explaining absorption by sunspots. It is found that there are two frequency ranges with very different behavior: (1) below the chromospheric acoustic cutoff frequency, and (2) above it. In the first case, which includes the 5 minute band, the f- and p₁-modes would be expected to suffer substantial absorption, but p-modes of higher radial order would not be damped sufficiently to account for observations. On the other hand, in the higher frequency range (≳5 mHz), damping lengths of f- and P₁-p₃ modes are smaller than or comparable to typical plage sizes, indicating that substantial absorption should occur.