A Statistical Study on The Frequency-Dependent Damping of Slow-mode Waves in Polar Plumes and Interplumes

TL;DR

This study statistically analyzes how the damping length of slow waves in solar polar regions depends on wave frequency, revealing an inverse power-law relationship and unexpected prevalence of short-period waves, with insights into turbulence characteristics.

Contribution

It provides the first large-sample statistical confirmation of frequency-dependent damping and turbulence features in polar plume and interplume regions using high-resolution EUV data.

Findings

Inverse power-law dependence of damping length on wave period

Short-period waves are more abundant than long-period waves in polar regions

Similar turbulence characteristics in plume and interplume regions

Abstract

We perform a statistical study on the frequency-dependent damping of slow waves propagating along polar plumes and interplumes in the solar corona. Analysis of a large sample of extreme ultraviolet (EUV) imaging data with high spatial and temporal resolutions obtained from AIA/SDO suggests an inverse power-law dependence of the damping length on the periodicity of slow waves (i.e., the shorter period oscillations exhibit longer damping lengths), in agreement with the previous case studies. Similar behavior is observed in both plume and interplume regions studied in AIA 171 \AA\ and AIA 193 \AA\ passbands. It is found that the short-period (2--6 min) waves are relatively more abundant than their long period (7--30 min) counterparts in contrast to the general belief that the polar regions are dominated by the longer-period slow waves. We also derived the slope of the power spectra ($\mathrm{\alpha}$, the power-law index) statistically to better understand the characteristics of turbulence present in the region. It is found that the $\mathrm{\alpha}$ values and their distributions are similar in both plume and interplume structures across the two AIA passbands. At the same time, the spread of these distributions also indicates the complexity of the underlying turbulence mechanism.