  We analyze a time sequence of He II 256.32 angstrom images obtained with
EIS/Hinode, sampling a small magnetic loop in magnetic network. Wavelet
analysis indicates 11-min periodicity close to the loop apex. We interprete
this oscillation as forcing through upward leakage by the fundamental acoustic
eigenmode of the underlying field-free cavity. The observed loop length
corresponds to the value predicted from this mechanism.
