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Hot Spine Loops and the Nature of a Late-phase Solar Flare
Liu, Yang; Aulanier, Guillaume; Sun, Xudong +4 more
The fan-spine magnetic topology is believed to be responsible for many curious features in solar explosive events. A spine field line links distinct flux domains, but direct observation of such a feature has been rare. Here we report a unique event observed by the Solar Dynamic Observatory where a set of hot coronal loops (over 10 MK) connected to…
Magnetohydrodynamic Modeling of the Solar Eruption on 2010 April 8
van Ballegooijen, A. A.; DeLuca, E. E.; Kliem, B. +1 more
The structure of the coronal magnetic field prior to eruptive processes and the conditions for the onset of eruption are important issues that can be addressed through studying the magnetohydrodynamic (MHD) stability and evolution of nonlinear force-free field (NLFFF) models. This paper uses data-constrained NLFFF models of a solar active region (…
The Cool Component and the Dichotomy, Lateral Expansion, and Axial Rotation of Solar X-Ray Jets
Moore, Ronald L.; Sterling, Alphonse C.; Falconer, David A. +1 more
We present results from a study of 54 polar X-ray jets that were observed in coronal X-ray movies from the X-ray Telescope on Hinode and had simultaneous coverage in movies of the cooler transition region (T ~ 105 K) taken in the He II 304 Å band of the Atmospheric Imaging Assembly (AIA) on Solar Dynamics Observatory. These dual observa…
Observing Coronal Nanoflares in Active Region Moss
Golub, Leon; Testa, Paola; Martínez-Sykora, Juan +12 more
The High-resolution Coronal Imager (Hi-C) has provided Fe XII 193Å images of the upper transition region moss at an unprecedented spatial (~0.''3-0.''4) and temporal (5.5 s) resolution. The Hi-C observations show in some moss regions variability on timescales down to ~15 s, significantly shorter than the minute-scale variability typically found in…
The Formation of IRIS Diagnostics. III. Near-ultraviolet Spectra and Images
De Pontieu, B.; Leenaarts, J.; Carlsson, M. +2 more
The Mg II h&k lines are the prime chromospheric diagnostics of NASA's Interface Region Imaging Spectrograph (IRIS). In the previous papers of this series, we used a realistic three-dimensional radiative magnetohydrodynamics model to calculate the h&k lines in detail and investigated how their spectral features relate to the underlying atmo…
A Global Wave-driven Magnetohydrodynamic Solar Model with a Unified Treatment of Open and Closed Magnetic Field Topologies
Gombosi, T. I.; Landi, E.; Jin, M. +3 more
We describe, analyze, and validate the recently developed Alfvén Wave Solar Model, a three-dimensional global model starting from the top of the chromosphere and extending into interplanetary space (out to 1-2 AU). This model solves the extended, two-temperature magnetohydrodynamics equations coupled to a wave kinetic equation for low-frequency Al…
Properties of a Solar Flare Kernel Observed by Hinode and SDO
Young, P. R.; Doschek, G. A.; Warren, H. P. +1 more
Flare kernels are compact features located in the solar chromosphere that are the sites of rapid heating and plasma upflow during the rise phase of flares. An example is presented from a M1.1 class flare in active region AR 11158 observed on 2011 February 16 07:44 UT for which the location of the upflow region seen by EUV Imaging Spectrometer (EIS…
Turbulent Dynamics in Solar Flare Sheet Structures Measured with Local Correlation Tracking
McKenzie, D. E.
High-resolution observations of the Sun's corona in extreme ultraviolet and soft X-rays have revealed a new world of complexity in the sheet-like structures connecting coronal mass ejections (CMEs) to the post-eruption flare arcades. This article presents initial findings from an exploration of dynamic flows in two flares observed with Hinode/XRT …
Ellerman Bombs—Evidence for Magnetic Reconnection in the Lower Solar Atmosphere
Doyle, J. G.; Madjarska, M. S.; Erdélyi, R. +4 more
The presence of photospheric magnetic reconnection has long been thought to give rise to short and impulsive events, such as Ellerman bombs (EBs) and Type II spicules. In this article, we combine high-resolution, high-cadence observations from the Interferometric BIdimensional Spectrometer and Rapid Oscillations in the Solar Atmosphere instruments…
Observational Quantification of the Energy Dissipated by Alfvén Waves in a Polar Coronal Hole: Evidence that Waves Drive the Fast Solar Wind
Hahn, M.; Savin, D. W.
We present a measurement of the energy carried and dissipated by Alfvén waves in a polar coronal hole. Alfvén waves have been proposed as the energy source that heats the corona and drives the solar wind. Previous work has shown that line widths decrease with height in coronal holes, which is a signature of wave damping, but have been unable to qu…