Broad and Bi-directional narrow quasi-periodic fast-propagating wave trains associated with a filament-driven halo CME on 2023 April 21

TL;DR

This study analyzes three distinct wave trains associated with a filament-driven halo CME on April 21, 2023, revealing their different propagation speeds, origins, and relationships with flare pulsations and filament eruption.

Contribution

It identifies and characterizes broad and bi-directional narrow QFP wave trains, linking their origins to flare energy release and filament unwinding motions.

Findings

Broad QFP wave train speed ranges from 300 to 1100 km/s.

Bi-directional narrow QFP wave trains have speeds of 1400 km/s (southward) and 550 km/s (northward).

Periodicities of wave trains match flare pulsations, indicating different excitation mechanisms.

Abstract

This paper presents three distinct wave trains that occurred on 2023 April 21: a broad quasi-periodic fast-propagating (QFP) wave train and a bi-directional narrow QFP wave train. The broad QFP wave train expands outward in a circular wavefront, while bi-directional narrow QFP wave trains propagate in the northward and southward directions, respectively. The concurrent presence of the wave trains offers a remarkable opportunity to investigate their respective triggering mechanisms. Measurement shows that the broad QFP wave train's speed is 300- 1100 km/s in different propagating directions. There is a significant difference in the speed of the bi-directional narrow QFP wave trains: the southward propagation achieves 1400 km/s, while the northward propagation only reaches about 550 km/s accompanied by a deceleration of about 1- 2 kms-2. Using the wavelet analysis, we find that the periodicity of the propagating wave trains in the southward and northward directions closely matches the quasi-periodic pulsations (QPPs) exhibited by the flares. Based on these results, the narrow QFP wave trains were most likely excited by the intermittent energy release in the accompanying flare. In contrast, the broad QFP wave train had a tight relationship with the erupting filament, probably attributed to the unwinding motion of the erupting filament or the leakage of the fast sausage wave train inside the filament body.