Search Publications
Modeling the propagation of coronal mass ejections with COCONUT: Implementation of the regularized Biot-Savart law flux rope model
Schmieder, B.; Poedts, S.; Guo, Y. +8 more
Context. Coronal mass ejections (CMEs) are rapid eruptions of magnetized plasma that occur on the Sun. They are known to be the main drivers of adverse space weather. The accurate tracking of their evolution in the heliosphere in numerical models is of the utmost importance for space weather forecasting.
Aims: The main objective of this paper…
Can Emission Measure Distributions Derived from Extreme-ultraviolet Images Accurately Constrain High-temperature Plasma?
Winebarger, Amy R.; Athiray, P. S.
Measuring the relative amount of high-temperature, low emission measure (EM) plasma is considered to be a smoking-gun observation to constrain the frequency of plasma heating in coronal structures. Often, narrowband, extreme-ultraviolet images, such as those obtained by the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO)…
Observation of Alfvén Wave Reflection in the Solar Chromosphere: Ponderomotive Force and First Ionization Potential Effect
Stangalini, Marco; Long, David M.; Brooks, David H. +7 more
We investigate the propagation of Alfvén waves in the solar chromosphere, distinguishing between upward and downward propagating waves. We find clear evidence for the reflection of waves in the chromosphere and differences in propagation between cases with waves interpreted to be resonant or nonresonant with the overlying coronal structures. This …
Small-scale magnetic flux emergence preceding a chain of energetic solar atmospheric events
Rouppe van der Voort, L. H. M.; Joshi, R.; Froment, C. +4 more
Context. Advancements in instrumentation have revealed a multitude of small-scale extreme-ultraviolet (EUV) events in the solar atmosphere and considerable effort is currently undergoing to unravel them.
Aims: Our aim is to employ high-resolution and high-sensitivity magnetograms to gain a detailed understanding of the magnetic origin of such…
Spectroscopic Observations of Coronal Rain Formation and Evolution Following an X2 Solar Flare
Warren, Harry P.; Ugarte-Urra, Ignacio; Brooks, David H. +2 more
A significant impediment to solving the coronal heating problem is that we currently only observe active region loops in their cooling phase. Previous studies showed that the evolution of cooling loop densities and apex temperatures is insensitive to the magnitude, duration, and location of energy deposition. Still, potential clues to how energy i…
Solar Flares and Magnetic Helicity
Toriumi, Shin; Park, Sung-Hong
Solar flares and coronal mass ejections are the largest energy-releasing phenomena in the current solar system. They cause drastic enhancements of electromagnetic waves of various wavelengths and sometimes eject coronal material into interplanetary space, disturbing the magnetic surroundings of orbiting planets, including the Earth. It is generall…
Spectroscopic evidence of cool plasma in quiet Sun small-scale brightenings detected by HRIEUV on board Solar Orbiter
Parenti, S.; Bocchialini, K.; Dolliou, A.
Context. A large number of small and short-lived EUV brightenings have been detected in the quiet Sun (QS) over the past three years by the High Resolution Imager of the Extreme Ultraviolet Imager (HRIEUV) on board Solar Orbiter. It remains uncertain whether these events reach coronal temperatures and, thus, whether they directly contribute to cor…
Assessing the Performance of the ADAPT and AFT Flux Transport Models Using In Situ Measurements from Multiple Satellites
Warren, Harry P.; Linton, Mark G.; Ugarte-Urra, Ignacio +7 more
The launches of Parker Solar Probe (Parker) and Solar Orbiter (SolO) are enabling a new era of solar wind studies that track the solar wind from its origin at the photosphere, through the corona, to multiple vantage points in the inner heliosphere. A key ingredient for these models is the input photospheric magnetic field map that provides the bou…
Spectroscopic Observations of the Solar Corona during the 2017 August 21 Total Solar Eclipse: Comparison of Spectral Line Widths and Doppler Shifts between Open and Closed Magnetic Structures
Landi, Enrico; Habbal, Shadia R.; Ding, Adalbert +5 more
The spectroscopic observations presented here were acquired during the 2017 August 21 total solar eclipse (TSE) with a three-channel partially multiplexed imaging spectrometer operating at extremely high orders (>50). The 4 R ⊙ extent of the slit in the north–south direction scanned the corona starting from the central meridian out t…
Super-Resolution of SOHO/MDI Magnetograms of Solar Active Regions Using SDO/HMI Data and an Attention-Aided Convolutional Neural Network
Xu, Yan; Wang, Haimin; Wang, Jason T. L. +4 more
Image super-resolution is an important subject in image processing and recognition. Here, we present an attention-aided convolutional neural network for solar image super-resolution. Our method, named SolarCNN, aims to enhance the quality of line-of-sight (LOS) magnetograms of solar active regions (ARs) collected by the Michelson Doppler Imager (M…