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

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{é}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.

Figures (12)

• Figure 1: The north-east limb of the Sun captured by AIA 304 Å at 17:54 UT is shown in panel (a). The blue box represents the region where the prominence eruption occurred. This region (inside the blue box) is displayed in panel (b). The green box in panel (b) represents the field of view (FOV) of IRIS/SJI. The top part of the jet, indicated by a white arrow, was not observed by IRIS. Panel (c) displays the X-ray flux observed by GOES from 17:30 UT to 19:00 UT. The red curve corresponds to the soft X-ray (SXR) flux, and the blue curve corresponds to the hard X-ray (HXR) flux. The first peak (black dashed vertical line) and the second peak (black solid vertical line) correspond to the C4.0 and C4.2 class solar flares. The first flare initiated at 17:43 UT (marked by the black arrow) and the second flare initiated at 18:15 UT.
• Figure 2: The time evolution of the jet-like prominence eruption observed by AIA 304 Å from 17:40 UT to 18:40 UT is shown here. An initial brightening and a stable filament/prominence are observed at 17:40 UT (panel (a)). The enhancement of the brightening and the rise of the filament are shown in panels (b), (c), and (d). Further, the northern leg of the prominence breaks at 17:52 UT, as indicated by the blue arrow in panel (e). As a result, the twisted jet-like structure forms, as visible in panels (g), (h), and (i). Later, the plasma falls back along the same path (panels (j) and (k)) and completely disappears at 18:40 ut (panel (l)). The animation starts from 17:39 UT to 18:41 UT. Total duration of the animation is 15s.
• Figure 3: The same signatures as Figure \ref{['fig:aia304']} but observed by IRIS/SJI 2796 Å.
• Figure 4: Same as Figure \ref{['fig:aia304']} but for AIA 171 Å filter. Additionally, the dark thread (i.e., cool plasma threads) is visible in panels (g), as indicated by the cyan arrow. The same dark threads are visible in panels (f) and (h). The animation starts from 17:39 UT to 18:41 UT. Total duration of the animation is 15s.
• Figure 5: Same as Figure \ref{['fig:aia304']}, but for hot AIA 94 Å filter. The animation starts from 17:39 UT to 18:41 UT. Total duration of the animation is 15s.