Multi-mode oscillations of sunspots

Oscillations of the magnetic field in the sunspot photosphere have been det ected by recent high-resolution, two-dimensional observations. Their power is concentrated in isolated small flux bundles (pores) outside of larger um brae and at the boundary between umbra and penumbra of larger spots. The sl ow body mode provides an explanation of the appearance of magnetic oscillat ions in small sunspots if the azimuth number m = 0, but also of the small f eatures piling up in rings in large sunspots. In the latter model the magne tic oscillations are the signature of the slow body mode with m much greate r than 1, which bears a resemblance to the well-known whispering gallery mo de in acoustics. The slow surface modes and fast body modes are also discus sed.