On excited frequencies for Alfv\'en waves in a coronal arcade

Abstract

The normal modes of oscillation for a magnetic arcade are used to analytically solve an initial value problem and estimate the power spectra of wave frequencies generated by a reconnection event in the solar corona. Over a realistic range of parameters, I find that such a disturbance generates a peak power at $\sim10$s$\mathrm{mHz}$ frequencies, but still substantial power up to $\sim4\mathrm{Hz}$. The cadence and sensitivity of current instrumentation does not allow observations of oscillations at these frequencies, but in the near future, new instrumentation will be able to probe this regime, and observationally determine its energetic importance.