Investigation of magnetic topology and triggering mechanisms of a C-class flare and active-region blowout jet

TL;DR

This study investigates the magnetic topology and triggering mechanisms of a C-class flare and active-region blowout jet by combining a data-constrained MHD simulation with a non-force-free field extrapolation. The extrapolated field reveals a pre-existing $3$D null and a co-located flux rope, and the simulation shows a sequence of slip-reconnection at the null’s QSLs followed by null-point reconnection that enables the flux rope eruption and jet; spontaneous creation and annihilation of null pairs occur with net topological degree conservation, aligning with observational brightenings in AIA channels. The results support a breakout-style scenario for blowout jets and illuminate how topology changes drive energy release and mass ejection in the solar corona. The work also validates the use of NFFF-based topology against multi-wavelength observations and highlights the role of null dynamics in jet initiation, while noting the limitations of incompressible ILES and suggesting future work with explicit resistivity and compressibility.

Abstract

Coronal jets are collimated plasma eruptions which are ubiquitous in the solar atmosphere. Believed to be triggered by magnetic reconnection, these jets can contribute to various phenomena, including coronal heating and particle acceleration. Coronal jets are a contemporary area of research with their onset mechanism meriting further attention. Importantly, a subclass of jets, the blowout jets, are particularly interesting because of their broad spire, suggesting substantial three-dimensional (3D) reconnection between open and closed field lines involving 3D null points. Consequently, here we explore the onset of a blowout jet associated with Active Region (AR) SPoCA 29093 detected by Spatial Possibilistic Clustering Algorithm (SPoCA). This AR produced a C1.1-class flare on 10 November 2022 and we investigate it using a data-constrained magnetohydrodynamic simulation initiated with a non force-free-field (NFFF) extrapolation of the photospheric magnetic field. Key elements of the extrapolated field lines are the presence of a 3D null and a magnetic flux rope (MFR) co-located with the jet activity region, the evolution of which is further traced in the simulation. The simulation suggests that magnetic reconnection is responsible for the evolution of the MFR, leading to a near-simultaneous onset of the flare and jet as observed by the AIA/SDO. In particular, the simulation shows spontaneous creation and annihilation of 3D null pairs via magnetic reconnection near the jet region. Such spontaneous null pair generation, in principle, can trigger or contribute to coronal jets; opening up a new avenue for further research.

Figures (12)

• Figure 1: The panel (a) depicts GOES ($1-8$) Å channel soft X-ray flux variation (blue curve) for about $19$ minutes starting from $03:00:00$ UT on November $10, 2022$. The flare starts at $03:09:00$ UT followed by a decrease after a peak at $03:12:00$ UT, resulting in a C $1.1$ class flare. The total positive and negative line-of-sight photospheric magnetic flux (red and green solid curves, respectively) remains constant for about 30 minutes, suggesting no significant flux change during the flare and jet (panel (b)). The change in positive and negative flux is well within $1\%$ and $0.5\%$, respectively.
• Figure 2: Figure depicts the evolution of a C $1.1$ class circular ribbon flare and a blowout jet activity using four AIA intensity channels (column-wise). Each panel spans over ($301.6 \times 255.2$) Mm covered with ($832 \times 704$) pixels in the x and y-axes, respectively. The evolution of flare and jet activity is shown in the first column (from left) for AIA 131 Å, in the second column for AIA 171 Å, in the third column for AIA 193 Å, and in the last column for AIA 304 Å. The first row (from top) depicts the observation at $03:00$ UT with no prominent activity, the second row represents the C $1.1$ class flare at $03:11$ UT and a jet around $03:16$ UT (shown in the third row) with the white box representing the ROI. The fourth and fifth rows represent the evolution of the jet around $03:17$ UT and $03:18$ UT, respectively. The Corresponding animation is available (in $2 \times 2$ panels) in the final HTML version with $t\in\{03:00, 03:19\}$ UT, where the flares and blowout jet can be better visualized in four AIA channels. The real time of the animation is $12$ s
• Figure 3: Figure depicts the detailed evolution of flare and jet using AIA $171$ Å channel, considering the same ROI. Initially, no significant activity is observed (panel (a)), and subsequently, pre-flare brightening starts to occur (panels (b)-(d)), followed by a C $1.1$ class flare prominent in panel (e) and a blowout jet (panel (f)-(i)). The corresponding animation is available in the final HTML version with $t\in\{03:00, 03:19\}$ UT, where the pre-flare brightening, flares, and a blowout jet can be better visualized. The real time of the animation is $18$ s.
• Figure 4: Panel (a) depicts the magnetogram used for extrapolation with ROI marked by a white rectangular box. The variation in $E_{n}$ and average of $|J \times B|$ for both original (O) and Rebinned (R) resolution are shown in panels (b) and (e), respectively. Plots show no significant differences. Panels (d) and (e) depict the 3D magnetic null point and flux rope topology found co-located with flare and jet activity for original and rebinned extrapolation, respectively. Both show similar magnetic topology. In panel (f), the fan field lines (in red) of 3D null are directed away from null, making topological degree $-1$ and plotted from rebinned extrapolation.
• Figure 5: This figure illustrates the slipping of the fan field lines (in cyan) through the plasma-i.e., slip-reconnection. The cyan field lines are traced from a fixed initial location for the integration. Plasma flows are drawn by blue arrows at the bottom boundary ($z = 0$) in all panels except (a), where no flow is present. In each panel, $\log(Q)$ is overlaid with the field lines. The fan field lines marked with white arrows move in a direction different from the plasma flow and traverse through high Q-value regions. The corresponding animation is available in the final HTML version with $t\in\{03:00, 03:03\}$ UT where the slippage of the field lines can be better visualized. The real time of the animation is $08$ s.