Search Publications
Ultra-high-resolution observations of persistent null-point reconnection in the solar corona
Barczynski, K.; Peter, H.; Chitta, L. P. +21 more
Magnetic reconnection is a key mechanism involved in solar eruptions and is also a prime possibility to heat the low corona to millions of degrees. Here, we present ultra-high-resolution extreme ultraviolet observations of persistent null-point reconnection in the corona at a scale of about 390 km over one hour observations of the Extreme-Ultravio…
Plasmoids, Flows, and Jets during Magnetic Reconnection in a Failed Solar Eruption
Antiochos, Spiro K.; Kumar, Pankaj; Cho, Kyung-Suk +3 more
We report a detailed analysis of a failed eruption and flare in active region 12018 on 2014 April 3 using multiwavelength observations from the Solar Dynamics Observatory/Atmospheric Imaging Assembly, IRIS, STEREO, and Hinode/Solar Optical Telescope. At least four jets were observed to emanate from the cusp of this small active region (large brigh…
Complete replacement of magnetic flux in a flux rope during a coronal mass ejection
Veronig, Astrid M.; Li, Ting; Wang, Yuming +5 more
Solar coronal mass ejections are the most energetic events in the Solar System. In their standard formation model, a magnetic flux rope builds up into a coronal mass ejection through magnetic reconnection that continually converts overlying, untwisted magnetic flux into twisted flux enveloping the pre-existing rope. However, only a minority of cor…
Spatial and Temporal Analysis of Quiescent Coronal Rain over an Active Region
Antolin, Patrick; Schad, Thomas A.; Froment, Clara +1 more
The solar corona produces coronal rain, hundreds of times colder and denser material than the surroundings. Coronal rain is known to be deeply linked to coronal heating, but its origin, dynamics, and morphology are still not well understood. The leading theory for its origin is thermal instability (TI) occurring in coronal loops in a state of ther…
Interrogating Solar Flare Loop Models with IRIS Observations 2: Plasma Properties, Energy Transport, and Future Directions
Kerr, Graham S.
During solar flares a tremendous amount of magnetic energy is released and transported through the Sun's atmosphere and out into the heliosphere. Despite over a century of study, many unresolved questions surrounding solar flares are still present. Among those are how does the solar plasma respond to flare energy deposition, and what are the impor…
Solar Flare Ribbon Fronts. I. Constraining Flare Energy Deposition with IRIS Spectroscopy
Polito, Vanessa; Xu, Yan; Kerr, Graham S. +2 more
Spectral lines formed at lower atmospheric layers show peculiar profiles at the "leading edge" of ribbons during solar flares. In particular, increased absorption of the BBSO/GST He I λ10830 line, as well as broad and centrally reversed profiles in the spectra of the Mg II and C II lines observed by the IRIS satellite, has been reported. In this w…
Ultra-high-resolution observations of plasmoid-mediated magnetic reconnection in the deep solar atmosphere
de la Cruz Rodríguez, Jaime; van Noort, Michiel; Rouppe van der Voort, Luc H. M.
Context. Magnetic reconnection in the deep solar atmosphere can give rise to enhanced emission in the Balmer hydrogen lines, a phenomenon referred to as Ellerman bombs.
Aims: To effectively trace magnetic reconnection below the canopy of chromospheric fibrils, we analyzed unique spectroscopic observations of Ellerman bombs in the Hα line.
Numerical Study on Excitation of Turbulence and Oscillation in Above-the-loop-top Region of a Solar Flare
Reeves, Katharine K.; Takasao, Shinsuke; Shibata, Kengo
Extreme-ultraviolet imaging spectroscopic observations often show an increase in line width around the loop-top or above-the-loop-top (ALT) region of solar flares, suggestive of turbulence. In addition, recent spectroscopic observations found the oscillation in the Doppler velocity around the ALT region. We performed 3D magnetohydrodynamic (MHD) s…
Solar flare hard X-rays from the anchor points of an eruptive filament
Volpara, Anna; Massa, Paolo; Krucker, Säm +7 more
Context. We present an analysis of a GOES M1.8 flare with excellent observational coverage in UV, extreme-UV (EUV), and X-ray, including observations from the Interface Region Imaging Spectrograph (IRIS), from the Solar Dynamics Observatory (SDO) with the Atmospheric Imaging Assembly (AIA), from the Hinode/EUV Imaging Spectrometer (EIS), from the …
Numerical Simulations and Observations of Mg II in the Solar Chromosphere
De Pontieu, Bart; Carlsson, Mats; Hansteen, Viggo H. +3 more
The Mg II h and k lines are among the best diagnostic tools of the upper solar chromosphere. This region of the atmosphere is of particular interest, as it is the lowest region of the Sun's atmosphere where the magnetic field is dominant in the energetics and dynamics, defining its structure. While highly successful in the photosphere and lower to…