Modelling of Reflective Propagating Slow-mode Wave in a Flaring Loop

TL;DR

This study uses 2.5D MHD simulations to model and confirm that observed quasi-periodic propagating intensity disturbances in flaring loops are reflected slow magnetosonic waves combined with mass flows, matching observations from multiple solar instruments.

Contribution

The paper presents a comprehensive 2.5D MHD model that reproduces observed propagating disturbances as reflected slow mode waves, clarifying their nature in flaring coronal loops.

Findings

Simulated intensity variations match SDO/AIA observations.

Reflected slow mode waves propagate at ~310 km/s.

Simulation confirms waves are consistent with SUMER Fe XIX Doppler measurements.

Abstract

Quasi-periodic propagating intensity disturbances have been observed in large coronal loops in EUV images over a decade, and are widely accepted to be slow magnetosonic waves. However, spectroscopic observations from Hinode/EIS revealed their association with persistent coronal upflows, making this interpretation debatable. We perform a 2.5D magnetohydrodynamic simulation to imitate the chromospheric evaporation and the following reflected patterns in a flare loop. Our model encompasses the corona, transition region, and chromosphere. We demonstrate that the quasi periodic propagating intensity variations captured by the synthesized \textit{Solar Dynamics Observatory}/Atmospheric Imaging Assembly (AIA) 131, 94~\AA~emission images match the previous observations well. With particle tracers in the simulation, we confirm that these quasi periodic propagating intensity variations consist of reflected slow mode waves and mass flows with an average speed of 310 km/s in an 80 Mm length loop with an average temperature of 9 MK. With the synthesized Doppler shift velocity and intensity maps of the \textit{Solar and Heliospheric Observatory}/Solar Ultraviolet Measurement of Emitted Radiation (SUMER) Fe XIX line emission, we confirm that these reflected slow mode waves are propagating waves.