Falling Threads During Solar Filament Eruptions

Rui Liu; Runbin Luo; Wensi Wang; Yidian Wu

REVIEW 3 major objections 5 minor 16 references

Falling Threads During Solar Filament Eruptions

T0 review · 3 major / 5 minor · reviewed 2026-08-07 · deepseek-v4-flash

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗

Pith's one-line read The paper argues that, in three filament eruptions, most draining mass lands on the hooked ends of flare ribbons because the mass rides field lines threading the filament's quasi-separatrix-layer boundary, and that reconnection stripping…

desk verdict The landing-site pattern is a nice new observation, but the paper's own peeling-reconnection mechanism undermines the inference that the mass was initially on QSL-threading field lines. read the letter →

arxiv 2505.22020 v1 pith:X3Q63TXA submitted 2025-05-28 astro-ph.SR

Yidian Wu , Rui Liu , Runbin Luo , Wensi Wang This is my paper

classification astro-ph.SR

keywords solarfilamentsfilamenteruptionsmassdrainagefallingthreadsflareribbonsquasi-separatrixlayersmagneticreconnectionflares

verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

The paper studies three solar filament eruptions in which cool material falls back to the surface in thin, nearly straight threads moving at 30–300 km/s. It finds a consistent pattern: most falling material lands on the hooked, J-shaped ends of flare ribbons, a small fraction lands inside the hooks, and almost none lands on the straight ribbon segments. From this pattern it concludes that before eruption most filament mass is not stored deep inside the magnetic flux rope, but is entrained by field lines that thread the rope's quasi-separatrix-layer boundary, whose footpoints are the hooked ribbons. It further concludes that reconnection involving those boundary field lines is the main agent that drains the mass out of the erupting filament. The paper also derives a density contrast for falling threads from a drag-versus-gravity balance, although its numerical model falls short of reproducing the observed speeds.

What carries the argument

The central object is the quasi-separatrix layer (QSL), a thin volume where the connectivity of magnetic field lines changes sharply, wrapping around the erupting flux rope, with its footpoints traced by the hooked flare ribbons. The argument treats falling threads as field-line tracers: where the material lands identifies which field lines carried it, and the QSL boundary is the only location consistent with the observed landing pattern. A second mechanism is the drag-force balance equation, which balances the component of gravity along an oblique flux tube against aerodynamic drag, yielding a density contrast estimate for the falling threads.

What would settle it

Track falling threads in three dimensions with paired spacecraft views and compare each thread's landing point with the pre-eruption footpoint of the field line it appears to follow, reconstructed from nonlinear force-free extrapolation; if a significant fraction of threads land away from those footpoints, or if a well-observed eruption shows substantial material draining onto straight ribbon segments, the QSL-storage conclusion would collapse.

Watch

Extended reading notes

Core claim

The paper claims that the location where erupting filament material lands on the solar surface directly maps where the mass was stored in the pre-eruption magnetic field. In all three events, falling threads land preferentially on the hooked segments of flare ribbons, which are the footprints of quasi-separatrix layers (QSLs) wrapping around the erupting flux rope. Only a small fraction lands inside the hooks, corresponding to the rope's inner field lines, and essentially none lands on the straight ribbons, which map arcade and post-flare loop field lines. The paper concludes that most filament mass is therefore entrained by field lines threading the QSL boundary of the filament field, and that reconnection between these mass-carrying boundary field lines and overlying arcade field lines, a process it calls 'ar-rf' reconnection, is the major cause of mass drainage during eruptions. In addition, the timing of hooked-ribbon brightening suggests that the earlier-formed QSL boundary was threaded by mass-loaded field lines while the later-formed boundary was depleted.

Load-bearing premise

The inference that pre-eruption filament mass is stored on QSL-threading field lines assumes that the falling plasma stays perfectly tied to magnetic field lines during descent, so that each landing site marks the footpoint of the field line that carried the mass; any substantial cross-field drift would break the mapping from landing points to the original mass location.

Editorial extensions

If this is right

Pre-eruption filament mass is largely stored on the boundary of the flux rope rather than in its interior, so eruption models should place cool dense material near the rope's QSL boundary.
Reconnection with the overlying arcade field ('ar-rf' reconnection) is the dominant mechanism that removes mass from an erupting filament, rather than simple gravitational draining of inner rope material.
The inward-sweeping motion of hooked ribbons reflects erosion of the flux rope by reconnection, with earlier-formed boundary field lines carrying mass and later-formed ones depleted.
Falling material should rarely land on straight ribbon segments, because those field lines carry little dense filament material.
The observed constant falling speeds can be used to estimate thread density contrasts, but the simple stratified-atmosphere model produces speeds too low, indicating that initial heights, initial densities, or additional forces need to be revised.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

If QSL-boundary mass storage is a generic property of erupting filaments, then a survey of many eruptions should find hooked-ribbon landings in every case with significant mass drainage, which would provide a quick statistical test of the claim.
The falling-thread tracer method could be applied to high-cadence, multi-viewpoint observations to diagnose QSL positions from kinematics alone, effectively mapping where mass sits inside magnetic structures before eruption.
The drag-based density contrast estimate, which gives electron densities around $2\times10^9\,\mathrm{cm}^{-3}$ for one thread, could be checked spectroscopically to see whether the inferred densities actually are present in falling threads.
The shortfall of the numerical model suggests that reconnection may give falling threads an initial downward impulse or that non-ideal effects such as viscosity and magnetic resistivity contribute to the drag; including these could reconcile the model with observed speeds.

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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Desk Editor's Note

read the letter

The genuinely new thing here is the empirical pattern: in three eruptions, falling filament threads land on the hooked segments of flare ribbons, not on the straight segments. That is a concrete observational constraint that any model of filament eruption has to explain. The paper also does two things well: it presents the kinematics transparently via stack plots and speed estimates, and it is honest when its own numerical model fails to match the observed speeds. The analytical drag model is simple, but it is used only to derive a density contrast; it is not fitted to reproduce a target.

The soft spot is the central interpretation. The paper concludes that most filament mass was initially on field lines threading the QSL boundary, because that is where the material lands. But the paper invokes ar-rf reconnection (Aulanier & Dudík 2019) as the mechanism: peeling reconnection rewires field lines, so a mass-bearing inner field line becomes boundary-like as outer layers are peeled off. Material on that inner field line then drains onto the current hooked ribbon, not inside the hook. The observed landing pattern is therefore equally consistent with an initially interior mass distribution that is progressively peeled and drained. The timing argument in Section 2.3 does not break this degeneracy: an earlier ribbon peak on the drained segment could just mark when the mass arrives, not when the field line first became QSL-threading. So "initially" is not uniquely constrained.

There are also the usual small-sample issues: three hand-picked events, landing sites identified by visual inspection of running-difference images, no counts or error bars. That makes the pattern suggestive rather than established. The density model assumes cd=1 and a rigid cylinder without justification, but since the result is used to feed a simulation that transparently fails, it is not a load-bearing flaw.

Who is this for? Solar physicists working on filament eruptions and flare ribbon morphology. The observational pattern deserves to be on record, but the interpretive conclusion should be softened. I'd recommend sending to peer review: the paper is coherent, honest, and the new pattern is worth refereeing. I'd ask the authors to qualify the conclusion and ideally add quantitative landing-site statistics.

Referee Report

3 major / 5 minor

Summary. The paper analyzes three filament eruptions (2011-11-09, 2012-02-10, 2023-09-14) in which cool filament material falls back to the solar surface during the eruption. Using running-difference images in AIA EUV channels and UV ribbon images, the authors report that most falling material lands on the hooked segments of flare ribbons, a small fraction lands inside the hooks, and almost none lands on the straight ribbon segments. From this pattern they conclude that before eruption most filament mass is entrained by field lines threading the quasi-separatrix layers (QSLs) at the boundary of the filament field, and that reconnection involving these field lines is the major cause of the drainage. They also propose a drag-balance model (Eq. 3) to estimate the density contrast of falling threads, and they run 1D hydrodynamic simulations that, for the measured thread parameters, produce falling speeds far below the observed values. The paper is transparent about this model failure and about the simplifying assumptions in the drag treatment.

Significance. If the central inference is correct, the paper would provide a new observational constraint on the pre-eruption mass distribution in solar filaments, linking draining threads to the QSL-boundary field lines and to ar-rf reconnection. The observed landing-site pattern is novel and potentially useful for testing models of filament eruption and flare ribbon morphology. The authors also honestly report the failure of their numerical model to reproduce observed speeds, which is a valuable negative result. However, the central conclusion is not uniquely forced by the data: as the paper itself invokes ar-rf reconnection, landing sites on the hooked ribbon may reflect post-reconnection connectivity rather than the pre-eruption field-line identity of the mass. The main contribution is therefore an interesting observational correlation whose interpretation requires additional modeling or a more quantitative analysis.

major comments (3)

[Section 3, first paragraph] The conclusion that 'initially most of the filament mass is entrained by field lines threading the QSL boundary' is underdetermined by the observed landing-site pattern. Under the ar-rf reconnection scheme the authors themselves invoke (Aulanier & Dudík 2019), a mass-loaded field line that reconnects produces new field lines whose footpoints lie on the hooked ribbon; material on an inner flux-rope field line could therefore be transferred to a boundary-like field line and subsequently land on the hooked ribbon, even though it was not on a QSL-threading field line before the eruption. The timing argument in Section 2.3 (earlier peak of the draining ribbon segment) does not resolve this degeneracy, because the ribbon brightening merely marks when mass arrives at the chromosphere, not when the field line first became QSL-threading. The authors should either add quantitative evidence that the falling threads trace pre-eruption field lines (e.g., NLFFF extrapolations of the falling paths or a reconnection-aware model) or soften the conclusion to state that the data show mass draining onto hooked-ribbon footpoints, without the 'initially' qualifier.
[Section 2.1 and Table 1] The central observational claim—'most', 'small fraction', and 'almost none'—is based on visual inspection of running-difference images, with no quantitative counts of falling threads, no uncertainty estimates for the landing-site classification, and no explicit criteria for selecting the three events as a representative or systematic sample. Because this landing-site pattern is the sole direct observational support for the QSL inference, the authors should provide a reproducible quantitative characterization (e.g., number of threads landing on hooked vs. straight vs. inside-hook regions per event, or a masked-area comparison) and assess the sensitivity of the classification to the choice of passband, image threshold, and observer. Without such quantification, the strength of the claimed pattern cannot be evaluated independently.
[Section 2.2.1] The inference that landing sites map one-to-one to the pre-eruption footpoints of mass-bearing field lines assumes that falling threads move strictly along magnetic field lines, as stated in the sentence 'the falling material must largely move along magnetic field lines, without sensing any force exerted by the magnetic field.' This assumption is asserted rather than tested. If pressure gradients, drag, or reconnection-driven flows cause cross-field motion, the mapping from landing position to pre-eruption field line fails. The authors should either validate this assumption (e.g., by comparing observed falling trajectories with NLFFF extrapolated field lines, as done in some earlier studies they cite) or explicitly present the QSL inference as conditional on the strict field-aligned flow assumption.

minor comments (5)

[Eq. (3) and Section 2.2.1] The drag model takes cd=1 and models the thread as a rigid cylinder with uniform cross-section; these are strong simplifications for a magnetized coronal plasma. The resulting density contrast (ρc ≈ 2.6) has no uncertainty estimate, and the connection to the numerical model should be described as an order-of-magnitude estimate rather than a measurement, given that the subsequent simulation with this value falls short of the observed speed by a factor of about six.
[Section 2.2.2] The numerical experiment with observed parameters reaches a maximum speed of 45.8 km/s versus the observed 269.8 km/s. The authors' discussion of underestimated height or density is reasonable, but the section would be clearer if it explicitly states that these experiments are diagnostic and not a validated predictive model of the observed events.
[Section 2.1.2] For the 2012-02-10 event, coronal dimmings are used as a proxy to help identify the hooked ribbons; the justification for this proxy would benefit from a more explicit statement of why the dimming regions map the footpoints of the eruptive structure and how they constrain the ribbon morphology.
[Figures 5–7] In the stack plots, the labeled speed values are sometimes difficult to read, and the correspondence between the slits in the images and the draining threads could be made clearer with arrows or matching colors; this would improve the reproducibility of the speed measurements.
[Title and abstract] The title contains an extra space ('F alling Threads'), and the abstract switches tense ('we proposed'); these minor typographical issues should be corrected in the final version.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the density-contrast estimate is fit-free and the numerical model fails to reproduce the observed speed, so the central quantitative step is not self-fulfilling.

full rationale

The paper's quantitative chain is self-contained rather than circular. The density contrast in Eq. (3) is obtained by balancing the assumed drag force with the effective gravity of an observed thread, using independently measured speed, length, and tilt angle; the cross-sectional area cancels by algebra, and no parameter is fitted to the speed that the model later aims to reproduce. The subsequent 1D simulation takes the reconstructed density as input and explicitly fails: the simulated maximum speed is 45.8 km/s versus the observed 269.8 km/s, which is the opposite of a fitted-input-called-prediction loop. The central inference about QSL-threading mass is an abductive interpretation of the landing-site pattern, not a definitional reduction: it assumes the falling material moves along field lines and adopts an external 3D flare-model mapping of hooked ribbons to QSL footprints (Janvier et al.; Aulanier & Dudík). The paper's own discussion of peeling 'ar-rf' reconnection exposes the underdetermination of the pre-eruption mass location, but that is a scientific inference weakness, not circularity. Self-citations (e.g., Wang et al. 2017; Gou et al. 2023; Wang et al. 2023) are used for the dimming proxy and footpoint behavior as external observational support, not as the load-bearing justification of the derivation, and the central interpretive framework is cited from non-overlapping authors. No step reduces by construction to its own input.

Assumptions & free parameters 3 free parameters · 5 assumptions · 0 invented entities

The central claim rests on the domain assumptions that falling material traces field lines and that the 3D standard flare model identifies hooked ribbons with QSL footprints. The analytical model introduces one free parameter (drag coefficient) and the numerical simulations introduce a filling-factor amplification. No new physical entities are postulated.

free parameters (3)

Drag coefficient c_d = 1
Set to unity in Eq. (1)-(3) for simplicity because there is no analytic MHD expression; directly scales the derived density contrast. Assumed, not measured.
Thread density amplification factor (filling factor) = 3-5 times observed
In numerical experiments (Section 2.2.2) the central thread density rho_th,0 is set to 3 to 5 times the observed value to account for an unknown filling factor in [0.001,0.2]. This is a free choice that changes the final speed.
Coronal base temperature T0 = 2 MK
Chosen for the model atmosphere in Section 2.2.2; sets the pressure and scale height. Not central to the observational claim, but affects the simulated speed.

assumptions (5)

domain assumption Falling filament material is frozen-in and moves along magnetic field lines.
Invoked in Section 2.2: 'the falling material must largely move along magnetic field lines, without sensing any force exerted by the magnetic field'. This is the basis for mapping landing sites to footpoints of mass-loaded field lines.
domain assumption Drag force balances the component of gravity parallel to the motion.
Eq. (2) states F_D = m_i g cos(theta). This force balance is assumed to hold during the observed constant-speed falls, allowing derivation of the density contrast.
domain assumption The standard 3D flare model applies to these events, with hooked ribbons mapping the QSL footprints of the flux rope.
Used throughout Section 1 and Section 3 to connect landing sites to QSL-threading field lines. If this mapping is wrong, the central inference fails.
standard math The corona is a fully ionized hydrogen plasma obeying the ideal gas law.
Used in the numerical model (Section 2.2.2) following Oliver et al. (2014), with p0 from the ideal gas law.
domain assumption Initial atmosphere is isothermal and gravitationally stratified.
Eq. (6) sets p and rho exponential with scale height H; this is a modeling choice in the simulation.

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Cite this review

Pith. "Pith review of Falling Threads During Solar Filament Eruptions." pith.science (2026). https://pith.science/paper/X3Q63TXA

@misc{pith2026250522020,
  author       = {Pith},
  title        = {Pith review of: Falling Threads During Solar Filament Eruptions},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/X3Q63TXA}},
  note         = {Machine review of arXiv:2505.22020}
}

read the original abstract

Mass drainage is frequently observed in solar filaments. During filament eruptions, falling material most likely flows along magnetic field lines, which may provide important clues for the magnetic structures of filaments. Here we study three filament eruptions exhibiting significant mass draining, often manifested as falling threads at a constant speed ranging between 30--300 km/s. We found that most of the falling material lands onto the hooked segments of flare ribbons, only a small fraction lands inside the hooks, and almost none lands onto the straight segments of ribbons. Based on these observations we surmise that before eruptions most of the filament mass is entrained by field lines threading the quasi-separatrix layers (QSLs), which wrap around the filament field and whose footpoints are mapped by the hooked ribbons, and that the magnetic reconnection involving these field lines is the major cause of the mass drainage during eruptions. Additionally, the light curves of the hooked ribbons suggest that during eruptions the earlier (later) QSL boundary of filaments is threaded by mass-loaded (depleted) field lines. By assuming that the constant-speed motion is due to a drag force balancing the gravity, we proposed a simplified analytical model to estimate the density contrast of the falling material. The estimated density contrast is then fed into a numerical model, in which filament threads fall along vertical magnetic field lines through a gravitationally stratified atmosphere. The resultant falling speeds, however, are short of observed values, which calls for further investigations.

Figures

Figures reproduced from arXiv: 2505.22020 by the authors.

**Figure 1.** Overview of the three events. AIA 304 ˚A pre-eruption images and HMI line-of-sight magnetograms are shown in the left and right columns, respectively. Filaments in 304 ˚A are delineated by blue dashed lines, which are superimposed in magnetograms [PITH_FULL_IMAGE:figures/full_fig_p013_1.png] view at source ↗

**Figure 2.** Filament eruption on 2011 November 9. Three snapshots of the event in 335 ˚A are shown in panels (a1–a3). The flare ribbons observed in 1600 ˚A are outlined by red curves and superimposed on the 335 ˚A difference images shown in (b1–b3), whose field-of-view is indicated by the white box in (a1–a3). The landing sites of falling threads are marked by cyan circles. The ribbon segments that are obscured by falling threa… view at source ↗

**Figure 3.** Filament eruption on 2012 February 10. Three snapshots of the event in 304 ˚A are shown in panels in the center column. The flare ribbons observed in 304 ˚A are outlined by red curves and superimposed on the 171 ˚A difference images shown in panels in the left and right columns. The landing sites of falling threads observed in 171 ˚A are marked by cyan circles. The blue contours outline the coronal dimmings observed… view at source ↗

Figures from the paper (9 more)

**Figure 4.** Figure 4: Filament eruption on 2023 September 14. Three snapshots of the event in 304 ˚A are shown in panels (a1–a3). The flare ribbons observed in 1600 ˚A are outlined by red curves and superimposed on the 171 ˚A difference images shown in (b1–b3), whose field-of-view is indica…

**Figure 5.** Figure 5: Estimation of falling speeds with stack plots derived from AIA 335 ˚A images for the 2011-11-09 event. Panel (a) shows a 335 ˚A image taken at 13:18 UT; (a1) zooms into the box region in (a) to show the flare ribbon at the eastern leg of the filament. The virtual slit …

**Figure 6.** Figure 6: Estimation of falling speeds with stack plots derived from AIA 304 ˚A images for the 2012-02-10 event. Similar to [PITH_FULL_IMAGE:figures/full_fig_p018_6.png]

**Figure 7.** Figure 7: Estimation of falling speeds with stack plots derived from AIA 304 ˚A images for the 2023-09-14 event. Similar to [PITH_FULL_IMAGE:figures/full_fig_p019_7.png]

**Figure 8.** Figure 8: Speeds and timing of falling threads in relation to the filament eruptions of interest. The top panels show the trajectories of the eruptive filaments obtained from the virtual slit f0 in Figs. 5-7. The filament speeds are calculated by the time derivative of the heigh…

**Figure 9.** Figure 9: Diagnostics on the density contrast of falling filament threads. (a & b) Paired images of the 2011-11-09 event observed simultaneously by SDO/AIA (a) and STEREO-B/EUVI (b). The blue crosses denote the visually selected two ends of a segment on a falling thread observed…

**Figure 10.** Figure 10: Dynamics of the simulated falling threads. The result using the measured thread parameters as input is shown in the top panels, and the measured values are highlighted by star symbols in the bottom panels. In (a) the density distribution of the falling thread is indic…

**Figure 11.** Figure 11: Light curves of different segments of the flare ribbons in the 2011-11-09 event. The background intensity has been subtracted from the light curves. (a) synoptic map of flare ribbons in 1600 ˚A, with each pixel shown by its maximum intensity during the flaring period.…

**Figure 12.** Figure 12: Light curves of different segments of the flare ribbons in the 2023-09-14 event. (a) synoptic map of flare ribbons in the ratio of 1600/1700 passbands to remove plages. (b) light curves for southern and northern ribbon, respectively. (c) light curves for the hooked an…

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Reference graph

Works this paper leans on

16 extracted references · 15 canonical work pages

[1]

E., Walsh, R

Alexander, C. E., Walsh, R. W., R´ egnier, S., et al. 2013, ApJL, 775, L32, doi: 10.1088/2041-8205/775/1/L32 Alexander, D., Liu, R., & Gilbert, H. R. 2006, ApJ, 653, 719, doi: 10.1086/508137 Aulanier, G., D´ emoulin, P., Mein, N., et al. 1999, A&A, 342, 867 Aulanier, G., DeVore, C. R., & Antiochos, S. K. 2002, ApJL, 567, L97, doi: 10.1086/339436 Aulanier,...

arXiv 2013
[2]

400" 350

Overview of the three events. AIA 304 ˚A pre-eruption images and HMI line-of-sight magnetograms are shown in the left and right columns, respectively. Filaments in 304 ˚A are delineated by blue dashed lines, which are superimposed in magnetograms. 14 Wu & Liu 450" 400" 350" 300" 250" a1)AIA 335 A 2011-11-09 13:19:27 360" 340" 320" 300" 280" 260" b1)AIA 33...

work page 2011
[3]

Filament eruption on 2011 November

work page 2011
[4]

Filament eruption on 2023 September

work page 2023
[5]

Filament eruption on 2012 February

work page 2012
[6]

600" 700

Estimation of falling speeds with stack plots derived from AIA 304 ˚A images for the 2012-02-10 event. Similar to Figure 5, the slit f0 is oriented along the direction of the filament eruption; the slits f1–f4 are oriented along the falling directions of the filament material. In (b1) the stack plot is superimposed by the light curve (blue) of the ribbon ...

work page 2012
[7]

Similar to Figure 6, the slit f0 is oriented along the direction of the filament eruption; the slits f1–f3 are oriented along the falling directions of the filament material

Estimation of falling speeds with stack plots derived from AIA 304 ˚A images for the 2023-09-14 event. Similar to Figure 6, the slit f0 is oriented along the direction of the filament eruption; the slits f1–f3 are oriented along the falling directions of the filament material. In (b1) the stack plot is superimposed by the light curve of the ribbon segment...

work page 2023
[8]

-700" -600

Speeds and timing of falling threads in relation to the filament eruptions of interest. The top panels show the trajectories of the eruptive filaments obtained from the virtual slit f0 in Figs. 5-7. The filament speeds are calculated by the time derivative of the height-time profiles. The falling speeds are obtained by linearly fitting the streaks of the ...

work page 2011

Show all 16 references

[9]

-200" 0

Three snapshots of the event in 335 ˚A are shown in panels (a1–a3). The flare ribbons observed in 1600 ˚A are outlined by red curves and superimposed on the 335 ˚A difference images shown in (b1–b3), whose field-of-view is indicated by the white box in (a1–a3). The landing sit...

2012
[10]

350" 300

Three snapshots of the event in 304 ˚A are shown in panels in the center column. The flare ribbons observed in 304 ˚A are outlined by red curves and superimposed on the 171 ˚A difference images shown in panels in the left and right columns. The landing sites of falling threads...

2023
[11]

-800" -600

Estimation of falling speeds with stack plots derived from AIA 335 ˚A images for the 2011-11-09 event. Panel (a) shows a 335 ˚A image taken at 13:18 UT; (a1) zooms into the box region in (a) to show the flare ribbon at the eastern leg of the filament. The virtual slit f0 (soli...

2011
[12]

20 Wu & Liu 12:50 13:10 13:30 13:50 Time(UT) 0 100 200 300 400Speed(km/s) b1) 124.2 360.8 58.8 123.7 112.1 cs filament drainage 1 drainage 2 drainage 3 drainage 4 drainage 5 0 100 200 300 400Height(Mm) a1) 2011-11-09 335Å-f0 filament height 18:30 19:00 19:30 20:00 20:30 Time(U...

2011
[14]

-800" -600

Three snapshots of the event in 304 ˚A are shown in panels (a1–a3). The flare ribbons observed in 1600 ˚A are outlined by red curves and superimposed on the 171 ˚A difference images shown in (b1–b3), whose field-of-view is indicated by the white box in (a1–a3). The landing sit...

2011
[15]

(a & b) Paired images of the 2011-11-09 event observed simultaneously by SDO/AIA (a) and STEREO-B/EUVI (b)

Diagnostics on the density contrast of falling filament threads. (a & b) Paired images of the 2011-11-09 event observed simultaneously by SDO/AIA (a) and STEREO-B/EUVI (b). The blue crosses denote the visually selected two ends of a segment on a falling thread observed by both...

2011
[16]

600" 700

Light curves of different segments of the flare ribbons in the 2011-11-09 event. The background intensity has been subtracted from the light curves. (a) synoptic map of flare ribbons in 1600 ˚A, with each pixel shown by its maximum intensity during the flaring period. (b) ligh...

2011
[17]

(a) synoptic map of flare ribbons in the ratio of 1600/1700 passbands to remove plages

Light curves of different segments of the flare ribbons in the 2023-09-14 event. (a) synoptic map of flare ribbons in the ratio of 1600/1700 passbands to remove plages. (b) light curves for southern and northern ribbon, respectively. (c) light curves for the hooked and straigh...

2023

Pith tools

Reviewed August 7, 2026 · model on record in the stance chip above.

[1] [1]

E., Walsh, R

Alexander, C. E., Walsh, R. W., R´ egnier, S., et al. 2013, ApJL, 775, L32, doi: 10.1088/2041-8205/775/1/L32 Alexander, D., Liu, R., & Gilbert, H. R. 2006, ApJ, 653, 719, doi: 10.1086/508137 Aulanier, G., D´ emoulin, P., Mein, N., et al. 1999, A&A, 342, 867 Aulanier, G., DeVore, C. R., & Antiochos, S. K. 2002, ApJL, 567, L97, doi: 10.1086/339436 Aulanier,...

arXiv 2013

[2] [2]

400" 350

Overview of the three events. AIA 304 ˚A pre-eruption images and HMI line-of-sight magnetograms are shown in the left and right columns, respectively. Filaments in 304 ˚A are delineated by blue dashed lines, which are superimposed in magnetograms. 14 Wu & Liu 450" 400" 350" 300" 250" a1)AIA 335 A 2011-11-09 13:19:27 360" 340" 320" 300" 280" 260" b1)AIA 33...

work page 2011

[3] [3]

Filament eruption on 2011 November

work page 2011

[4] [4]

Filament eruption on 2023 September

work page 2023

[5] [5]

Filament eruption on 2012 February

work page 2012

[6] [6]

600" 700

Estimation of falling speeds with stack plots derived from AIA 304 ˚A images for the 2012-02-10 event. Similar to Figure 5, the slit f0 is oriented along the direction of the filament eruption; the slits f1–f4 are oriented along the falling directions of the filament material. In (b1) the stack plot is superimposed by the light curve (blue) of the ribbon ...

work page 2012

[7] [7]

Similar to Figure 6, the slit f0 is oriented along the direction of the filament eruption; the slits f1–f3 are oriented along the falling directions of the filament material

Estimation of falling speeds with stack plots derived from AIA 304 ˚A images for the 2023-09-14 event. Similar to Figure 6, the slit f0 is oriented along the direction of the filament eruption; the slits f1–f3 are oriented along the falling directions of the filament material. In (b1) the stack plot is superimposed by the light curve of the ribbon segment...

work page 2023

[8] [8]

-700" -600

Speeds and timing of falling threads in relation to the filament eruptions of interest. The top panels show the trajectories of the eruptive filaments obtained from the virtual slit f0 in Figs. 5-7. The filament speeds are calculated by the time derivative of the height-time profiles. The falling speeds are obtained by linearly fitting the streaks of the ...

work page 2011