Abstract
The background field is assumed to play prime role in the erupting structures like prominences. In the flux rope models, the critical decay index ($n_c$) is a measure of the rate at which background field intensity decreases with height over the flux rope or erupting structure. In the real observations, the critical height of the background field is unknown, so a typical value of $n_{c}=1.5$ is adopted from the numerical studies. In this study, we determined the $n_c$ of 10 prominence eruptions (PEs). The prominence height in 3D is derived from two-perspective observations of \textit{Solar Dynamics Observatory} and \textit{Solar TErrestrial RElations Observatory}. Synoptic maps of photospheric radial magnetic field are used to construct the background field in the corona. During the eruption, the height-time curve of the sample events exhibits the slow and fast-rise phases and is fitted with the linear-cum-exponential model. From this model, the onset height of fast-rise motion is determined and is considered as the critical height for the onset of the torus-instability because the erupting structure is allowed to expand exponentially provided there is no strapping background field. Corresponding to the critical height, the $n_c$ values of our sample events are varied to be in the range of 0.8-1.3. Additionally, the kinematic analysis suggests that the acceleration of PEs associated with flares are significantly enhanced compared to flare-less PEs. We found that the flare magnetic reconnection is the dominant contributor than the torus-instability to the acceleration process during the fast-rise phase of flare-associated PEs in low corona ($<1.3R_{\odot}$).
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.