Network Loop Oscillations with EIS/Hinode

TL;DR

This paper investigates 11-minute oscillations in a solar magnetic loop observed with EIS/Hinode, attributing them to acoustic wave leakage from a field-free cavity, and confirms the predicted loop length from this model.

Contribution

It provides evidence linking observed loop oscillations to acoustic leakage mechanisms, supporting theoretical predictions about wave propagation in solar magnetic structures.

Findings

Detected 11-minute periodicity in loop oscillations

Oscillations attributed to upward leakage of fundamental acoustic mode

Loop length matches theoretical predictions from the leakage mechanism

Abstract

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.