Search Publications
Flare-productive active regions
Toriumi, Shin; Wang, Haimin
Strong solar flares and coronal mass ejections, here defined not only as the bursts of electromagnetic radiation but as the entire process in which magnetic energy is released through magnetic reconnection and plasma instability, emanate from active regions (ARs) in which high magnetic non-potentiality resides in a wide variety of forms. This revi…
New View of the Solar Chromosphere
De Pontieu, Bart; Carlsson, Mats; Hansteen, Viggo H.
The solar chromosphere forms a crucial, yet complex and until recently poorly understood, interface between the solar photosphere and the heliosphere. Advances in high-resolution instrumentation, adaptive optics, image reconstruction techniques, and space-based observatories allow unprecedented high-resolution views of the finely structured and hi…
Quiet Sun magnetic fields: an observational view
Orozco Suárez, David; Bellot Rubio, Luis
The quiet Sun is the region of the solar surface outside of sunspots, pores, and plages. In continuum intensity it appears dominated by granular convection. However, in polarized light the quiet Sun exhibits impressive magnetic activity on a broad range of scales, from the 30,000 km of supergranular cells down to the smallest magnetic features of …
Achievements of Hinode in the first eleven years
Solanki, Sami K.; Tiwari, Sanjiv K.; Reeves, Katharine K. +33 more
Hinode is Japan's third solar mission following Hinotori (1981-1982) and Yohkoh (1991-2001): it was launched on 2006 September 22 and is in operation currently. Hinode carries three instruments: the Solar Optical Telescope, the X-Ray Telescope, and the EUV Imaging Spectrometer. These instruments were built under international collaboration with th…
Coronal bright points
Madjarska, Maria S.
Coronal bright points (CBPs) are a fundamental class of solar activity. They represent a set of low-corona small-scale loops with enhanced emission in the extreme-ultraviolet and X-ray spectrum that connect magnetic flux concentrations of opposite polarities. CBPs are one of the main building blocks of the solar atmosphere outside active regions u…
Evidence of ubiquitous Alfvén pulses transporting energy from the photosphere to the upper chromosphere
Wang, Yuming; Liu, Jiajia; Erdélyi, Robert +2 more
The multi-million degree temperature increase from the middle to the upper solar atmosphere is one of the most fascinating puzzles in plasma-astrophysics. Although magnetic waves might transport enough energy from the photosphere to heat up the local chromosphere and corona, observationally validating their ubiquity has proved challenging. Here, w…
Stokes inversion based on convolutional neural networks
Asensio Ramos, A.; Díaz Baso, C. J.
Context. Spectropolarimetric inversions are routinely used in the field of solar physics for the extraction of physical information from observations. The application to two-dimensional fields of view often requires the use of supercomputers with parallelized inversion codes. Even in this case, the computing time spent on the process is still very…
First Detection of Plasmoids from Breakout Reconnection on the Sun
Antiochos, Spiro K.; Kumar, Pankaj; DeVore, C. Richard +2 more
Transient collimated plasma ejections (jets) occur frequently throughout the solar corona, in active regions, quiet Sun, and coronal holes. Although magnetic reconnection is generally agreed to be the mechanism of energy release in jets, the factors that dictate the location and rate of reconnection remain unclear. Our previous studies demonstrate…
Properties of Slow Magnetoacoustic Oscillations of Solar Coronal Loops by Multi-instrumental Observations
Moon, Y. -J.; Nakariakov, V. M.; Kumar, P. +3 more
Rapidly decaying oscillations of the thermal emission detected in the decay phase of solar and stellar flares are usually interpreted as standing or sloshing (reflecting) slow magnetoacoustic oscillations. We determine the scalings of the oscillation periods, damping times, and amplitudes with the temperature, considering both standing and sloshin…
Record-breaking Coronal Magnetic Field in Solar Active Region 12673
Fleishman, Gregory D.; Anfinogentov, Sergey A.; Stupishin, Alexey G. +1 more
The strongest magnetic fields on the Sun are routinely detected at dark sunspots. The magnitude of the field is typically about 3000 G, with only a few exceptions that reported the magnetic field in excess of 5000 G. Given that the magnetic field decreases with height in the solar atmosphere, no coronal magnetic field above ∼2000 G has ever been r…