Propagating Disturbances along fan-like coronal loops in an active region

TL;DR

This study investigates propagating disturbances in active region fan-like coronal loops, analyzing spectroscopic and imaging data to determine whether they are caused by slow MHD waves or high-speed upflows, thus enhancing understanding of solar coronal dynamics.

Contribution

The paper combines spectroscopic and imaging observations to distinguish between wave and flow origins of disturbances in coronal loops, providing new insights into their nature.

Findings

Oscillations observed at different locations in the loops.

Variations in line parameters suggest mixed wave and flow signatures.

Improved understanding of the origin of propagating disturbances.

Abstract

Propagating disturbances are often observed in active region fan-like coronal loops. They were thought to be due to slow mode MHD waves based on some of the observed properties. But the recent studies involving spectroscopy indicate that they could be due to high speed quasi-periodic upflows which are difficult to distinguish from upward propagating slow waves. In this context, we have studied a fan loop structure in the active region AR 11465 using simultaneous spectroscopic and imaging observations from Extreme-ultraviolet Imaging Spectrometer (EIS) on board Hinode and Atmospheric Imaging Assembly (AIA) on board SDO. Analysis of the data shows significant oscillations at different locations. We explore the variations in different line parameters to determine whether the waves or flows could cause these oscillations to improve the current understanding on the nature of these disturbances.