An Estimate of P-Mode Damping by Wave Leakage

Abstract

High-cadence TRACE observations show that outward-propagating intensity dis- turbances are a common feature in large, quiescent coronal loops. Analysis of the fre- quency distribution of these modes shows peaks at both three- and five-minute periods, indicating that they may be driven by the solar surface oscillations (p modes). The energy flux contained within the coronal intensity disturbances is of the order of (1.1 ± 0.4) × 10 3 ergs cm −2 s −1 . A simple order-of-magnitude estimate of the damping rate of the rele- vant p modes allows us to put an observational constraint on the damping of p modes and shows that leakage into the overlying coronal atmosphere might be able to account for a significant fraction of p-mode damping.