Is There Alfvénic Turbulence at the Apex of Solar Coronal Loops?

A long-standing problem in astrophysics is to explain the heating of the solar corona to over a million degrees, which is orders of magnitude higher than the photosphere beneath it. One proposed solution is that the necessary energy is carried from lower layers of the Sun by Alfvén waves and released by Alfvénic turbulence. In coronal magnetic loops, Alfvén waves from opposite footpoints could collide at the loop apex and drive turbulence. The resulting energy cascade would cause increased velocity perturbations at smaller spatial scales. Thus, the Fourier power spectrum of wave-driven velocity perturbations at the loop apex would have more power at high frequencies compared to the power spectrum closer to the loop footpoints. In order to investigate these potential power spectrum variations, we surveyed a variety of coronal loops in data from the Coronal Multi-channel Polarimeter at the Mauna Loa Solar Observatory. We fit a power law model to the power spectra taken at different points along these loops. We then analyzed the variation in the fitted power-law indices and other parameters as a function of height, length, and other loop properties. Here, we present our findings.