Kinematics and Untwisting Motion of an Intriguing Jet-like Prominence Eruption

TL;DR

This study analyzes the kinematics and untwisting motion of a prominence eruption that produced a blowout jet, revealing detailed plasma velocities, oscillations, and associated solar phenomena like flares and a CME.

Contribution

It provides new insights into the dynamics of prominence eruptions and the associated jet's untwisting motion, including detailed velocity measurements and wave analysis.

Findings

Jet speeds ranged from 125 to 593 km/s.

Transverse oscillations propagated at 267 km/s, consistent with Alfvén waves.

A CME with a speed of approximately 250 km/s was associated with the event.

Abstract

We aim to investigate the blowout jet-like prominence eruption, which occurred on October 6$^{th}$, 2023, with the help of imaging and spectroscopic observations. Firstly, the prominence rises slowly with a speed of 33 km/s, followed by a fast rise (i.e., 338 km/s). Later, the northern leg breaks completely, and the eruption forms the blowout jet. The jet consists of different plasma threads, which show a range of upflow (i.e., 125 to 593 km/s) and downflow velocities (i.e., 43 to 158 km/s). The jet plasma column exhibits transverse oscillations, and this motion (untwisting motion) propagate at the speed of 267 km/s, are consistent with being Alfev{\'e}n waves. The transverse motion has the time period, amplitude, and transverse velocity of 1332 s, 26.19 Mm, and 126.18$\pm$7.27 km/s, respectively, and this transverse oscillation decays over time. Interestingly, the different plasma threads within the jet's body exhibit decayless transverse oscillations, and these decayless oscillations are related to the main decaying transverse oscillation. The transverse velocity of these decayless oscillations ranges from 66 to 30 km/s, the amplitudes from 8.52 to 2.74 Mm, and periods from 811 to 406 s. In addition, the spectroscopic analysis reveals Si~{\sc iv} lines are forming in the optically thick conditions in high electron density regions (i.e., near the base of the blowout jet). Lastly, we mention that two weak C-class flares occurred during this event, and further, one CME also occurred, which propagated with the speed of $\sim$250 km/s.