The Relation Between Solar Eruption Topologies and Observed Flare Features. I. Flare Ribbons

Savcheva, Antonia; Pariat, É.; McKillop, S.; McCauley, Patrick; Hanson, E.; Su, Yingna; Werner, Elisabeth; DeLuca, E. E.

doi:10.1088/0004-637x/810/2/96

Cited by 101 publications

(127 citation statements)

References 52 publications

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“…The footpoints of these loop-like brightenings are the same as the locations of the flare ribbons during the subsequent X2-class flare. These brightenings indicate ongoing magnetic reconnection along the quasi-separatrix layers (Priest & Démoulin 1995;Démoulin et al 1996Démoulin et al , 1997Titov et al 2002;Savcheva et al 2015) involved in the flare. An overview of the flare evolution, as observed by SDO/AIA in the 131 Åband and the IRIS SJI in the 1330 Åfilter, is shown in Figure 5.…”

Section: Evolution Of the Flarementioning

confidence: 98%

Simultaneous Iris and Hinode/Eis Observations and Modeling of the 2014 October 27 X2.0 CLASS Flare

Polito

Reep

Reeves

et al. 2016

ApJ

105

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We present a study of the X2-class flare which occurred on 2014 October 27 and was observed with the Interface Region Imaging Spectrograph (IRIS) and the EUV Imaging Spectrometer (EIS) on board the Hinode satellite. Thanks to the high cadence and spatial resolution of the IRIS and EIS instruments, we are able to compare simultaneous observations of the Fe XXI1354.08 Åand Fe XXIII263.77 Åhigh-temperature emission (10 MK) in the flare ribbon during the chromospheric evaporation phase. We find that IRIS observes completely blueshifted Fe XXIline profiles, up to 200 km s −1 during the rise phase of the flare, indicating that the site of the plasma upflows is resolved by IRIS. In contrast, the Fe XXIIIline is often asymmetric, which we interpret as being due to the lower spatial resolution of EIS. Temperature estimates from SDO/AIA and Hinode/XRT show that hot emission (log(T[K]) >7.2) is first concentrated at the footpoints before filling the loops. Density-sensitive lines from IRIS and EIS give estimates of electron number density of 10 12 cm −3 in the transition region lines and 10 10 cm −3 in the coronal lines during the impulsive phase. In order to compare the observational results against theoretical predictions, we have run a simulation of a flare loop undergoing heating using the HYDRAD 1D hydro code. We find that the simulated plasma parameters are close to the observed values that are obtained with IRIS, Hinode, and AIA. These results support an electron beam heating model rather than a purely thermal conduction model as the driving mechanism for this flare.

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Section: Evolution Of the Flarementioning

confidence: 98%

Simultaneous Iris and Hinode/Eis Observations and Modeling of the 2014 October 27 X2.0 CLASS Flare

Polito

Reep

Reeves

et al. 2016

ApJ

105

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“…In particular, we use two of the active regions studied in Savcheva et al (2015Savcheva et al ( , 2016, one on 2007 February 12 and the other on 2010 August 7. The flux rope insertion method (van Ballegooijen 2004) is used to produce the NLFFF models.…”

Section: Nonlinear Force-free Field Modelsmentioning

confidence: 99%

“…More details on the observations can be found in Savcheva et al (2015). Some selected magnetic field lines and QSLs on a slice of the NLFFF model are displayed in Figure 10 (0, 0, 0) the coordinates of the central point on the disk.…”

Section: Nonlinear Force-free Field Modelsmentioning

confidence: 99%

“…The twist number method is described is Section 2. Results of the method's application to the Titov-Démoulin model (Titov & Démoulin 1999), magnetohydrodynamic (MHD) numerical simulations (Leake et al 2013(Leake et al , 2014, and nonlinear force-free field (NLFFF) models (Savcheva et al 2015(Savcheva et al , 2016 are presented in Section 3. We finally provide a summary and make a discussion in Section 4.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic Helicity Estimations in Models and Observations of the Solar Magnetic Field. III. Twist Number Method

Guo

Pariat

Valori

et al. 2017

ApJ

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We study the writhe, twist and magnetic helicity of different magnetic flux ropes, based on models of the solar coronal magnetic field structure. These include an analytical force-free Titov-Démoulin equilibrium solution, non forcefree magnetohydrodynamic simulations, and nonlinear force-free magnetic field models. The geometrical boundary of the magnetic flux rope is determined by the quasi-separatrix layer and the bottom surface, and the axis curve of the flux rope is determined by its overall orientation. The twist is computed by arXiv:1704.02096v1 [astro-ph.SR] 7 Apr 2017 -2 -the Berger-Prior formula that is suitable for arbitrary geometry and both forcefree and non-force-free models. The magnetic helicity is estimated by the twist multiplied by the square of the axial magnetic flux. We compare the obtained values with those derived by a finite volume helicity estimation method. We find that the magnetic helicity obtained with the twist method agrees with the helicity carried by the purely current-carrying part of the field within uncertainties for most test cases. It is also found that the current-carrying part of the model field is relatively significant at the very location of the magnetic flux rope. This qualitatively explains the agreement between the magnetic helicity computed by the twist method and the helicity contributed purely by the current-carrying magnetic field.

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“…NLFFF models have been widely adopted to study magnetic field structures in the solar atmosphere, for instance, magnetic flux ropes (Canou et al 2009;Su et al 2009;Canou & Amari 2010;Cheng et al 2010;Guo et al 2010aGuo et al , 2010bJing et al 2010), magnetic null points (Zhang et al 2012;Sun et al 2013Sun et al , 2014, and quasi-separatrix layers (Savcheva et al 2012(Savcheva et al , 2015Guo et al 2013;Zhao et al 2014;Yang et al 2015). Most of them are modeled in Cartesian coordinates, although some models are reconstructed in spherical geometry (Su et al 2009;Tadesse et al 2011;Guo et al 2012) or with tetrahedral meshes (Amari et al 2014b).…”

Section: Introductionmentioning

confidence: 99%

Magneto-Frictional Modeling of Coronal Nonlinear Force-Free Fields. Ii. Application to Observations

Guo

Xia

Keppens

2016

ApJ

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A magneto-frictional module has been implemented and tested in the Message Passing Interface Adaptive Mesh Refinement Versatile Advection Code (MPI-AMRVAC) in the first paper of this series. Here, we apply the magneto-frictional method to observations to demonstrate its applicability in both Cartesian and spherical coordinates, and in uniform and block-adaptive octree grids. We first reconstruct a nonlinear force-free field (NLFFF) on a uniform grid of 180 3 cells in Cartesian coordinates, with boundary conditions provided by the vector magnetic field observed by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) at 06:00 UT on 2010 November 11 in active region NOAA 11123. The reconstructed NLFFF successfully reproduces the sheared and twisted field lines and magnetic null points. Next, we adopt a three-level block-adaptive grid to model the same active region with a higher spatial resolution on the bottom boundary and a coarser treatment of regions higher up. The force-free and divergence-free metrics obtained are comparable to the run with a uniform grid, and the reconstructed field topology is also very similar. Finally, a group of active regions, including NOAA 11401, 11402, 11405, and 11407, observed at 03:00 UT on 2012 January 23 by SDO/HMI is modeled with a five-level block-adaptive grid in spherical coordinates, where we reach a local resolution of  0 . 06 pixel −1 in an area of 790 Mm×604 Mm. Local high spatial resolution and a large field of view in NLFFF modeling can be achieved simultaneously in parallel and block-adaptive magneto-frictional relaxations.

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The Relation Between Solar Eruption Topologies and Observed Flare Features. I. Flare Ribbons

Cited by 101 publications

References 52 publications

Simultaneous Iris and Hinode/Eis Observations and Modeling of the 2014 October 27 X2.0 CLASS Flare

Simultaneous Iris and Hinode/Eis Observations and Modeling of the 2014 October 27 X2.0 CLASS Flare

Magnetic Helicity Estimations in Models and Observations of the Solar Magnetic Field. III. Twist Number Method

Magneto-Frictional Modeling of Coronal Nonlinear Force-Free Fields. Ii. Application to Observations

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