Physical origin of the 50-minute 304 Å periodicity

Identify the physical cause of the approximately 50-minute periodic intensity variation observed in the 304 Å emission from the loop brightened by the CME2 downflow.

Background

The paper finds an apparent 50-minute periodicity in the 304 Å light curve measured above the loop arcade affected by the falling CME2 material. No comparable variation is detected in the hotter AIA bandpasses. Although the period resembles those reported for oscillations of solar prominences and filaments, the authors do not identify a corresponding physical oscillation in the observed loop or brightening.

The origin of the periodic signal therefore remains unresolved. Determining whether it reflects an actual oscillation, coronal-rain dynamics, instrumental or observational effects, or another process would clarify the interpretation of the low-temperature response to the CME-remnant downflow.