Understanding the Role of Mass-Unloading in a Filament Eruption

Abstract

We describe a partial filament eruption on 11 December 2011 that demonstrates that the inclusion of mass is an important next step for understanding solar eruptions. Observations from the Solar Terrestrial Relations Observatory-Behind (STEREO-B) and the Solar Dynamics Observatory (SDO) spacecraft were used to remove line-of-sight projection effects in filament motion and correlate the effect of plasma dynamics with the evolution of the filament height. Flux cancellation and nearby flux emergence are shown to have played a role in increasing the height of the filament prior to eruption. The two viewpoints allow the quantitative estimation of a large mass-unloading, the subsequent radial expansion, and the eruption of the filament to be investigated. A 1.8 to 4.1 lower-limit ratio between gravitational and magnetic-tension forces was found. We therefore conclude that following the loss-of-equilibrium of the flux-rope, the radial expansion of the flux-rope was restrained by the filamentary material until 70% of the mass had evacuated the structure through massunloading.

Modeling the Effect of Mass-draining on Prominence Eruptions

“…The increase in height observed by Jenkins et al (2018) after the prominence underwent mass-draining was > 60 Mm before leaving the field-of-view. The simple model described here predicts the maximum possible increase in height for the same amount of mass-draining to be up to 1.7 Mm, assuming the final state is also in equilibrium.…”

“…Hence, the large increase in the height of the observed prominence (60 Mm) shortly after the draining of mass could be interpreted as being caused by the flux rope losing equilibrium and erupting into the heliosphere due to the torus instability. The prominence observed by Jenkins et al (2018) did successfully erupt and was later observed as a CME by multiple coronagraphs.…”

“…Specifically, D is half the width, and L y the length, of the red-dashed box in Figure 3b of Jenkins et al (2018). The value of B Phot is the average strength of the magnetic field within the bounds of the red-dashed box in Figure 3a of Jenkins et al (2018). The results of the application of these values to the model are shown in Figure 6.…”

“…However, novel observations and hydrostatic modeling are beginning to suggest that mass may be able to influence the local and global properties of magnetic flux ropes (Low et al 2003;Petrie et al 2007;Seaton et al 2011;Gunár et al 2013;Bi et al 2014;Reva et al 2017;Jenkins et al 2018). In particular, the Shafranov shift as explored in Blokland & Keppens (2011) details how varying the gravity term in their 2D magnetohydrostatic (MHS) model can cause the axis of their flux rope to decrease the height.…”

Unambiguous Evidence of Coronal Implosions during Solar Eruptions and Flares

“…As the local plasma density and thus gravitational pull are reduced, the filament field would inflate, simultaneously pushing the overlying arcade outward, which is the opposite of an implosion. Similarly, during the eruption in Figure 9(d), such a process would occur if mass along the filament field could drain down (see relevant studies, e.g., Fong et al 2002;Bi et al 2014;Fan 2017;Jenkins et al 2018, pointing out that substantial filament material drains down that may influence the dynamics) and also spread into a larger volume. Moreover, as the filament field becomes more vertical, the draining could increase, further inflating the surrounding field.…”