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Multi-Scale Variability of Coronal Loops Set by Thermal Non-Equilibrium and Instability as a Probe for Coronal Heating
Antolin, Patrick; Froment, Clara
Solar coronal loops are the building blocks of the solar corona. These dynamic structures are shaped by the magnetic field that expands into the solar atmosphere. They can be observed in X-ray and extreme ultraviolet (EUV), revealing the high plasma temperature of the corona. However, the dissipation of magnetic energy to heat the plasma to millio…
Interrogating Solar Flare Loop Models with IRIS Observations 1: Overview of the Models, and Mass flows
Kerr, Graham S.
Solar and stellar flares are transient yet dramatic events in the atmospheres of the Sun or stars, during which vast amounts of magnetic energy is liberated. This energy is subsequently transported through the solar atmosphere or into the heliosphere, and together with coronal mass ejections flares comprise a fundamental component of space weather…
Solar Jets: SDO and IRIS Observations in the Perspective of New MHD Simulations
Schmieder, Brigitte
Solar jets are observed as collimated plasma beams over a large range of temperatures and wavelengths. They have been observed in H α and optical lines for more than 50 years and called surges. The term "jet" comes from X-ray observations after the launch of the Yohkoh satellite in 1991. They are the means of transporting energy through the helios…
Near-Ultraviolet Continuum Modeling of the 1985 April 12 Great Flare of AD Leo
Kowalski, Adam F.
White-light stellar flares are now reported by the thousands in long-baseline, high-precision, broad-band photometry from missions like \emph{Kepler}, K2, and TESS. These observations are crucial inputs for assessments of biosignatures in exoplanetary atmospheres and surface ultraviolet radiation dosages for habitable zone planets around low-mass …
Rapid variations of Si IV spectra in a flare observed by interface region imaging spectrograph at a sub-second cadence
Polito, Vanessa; Yu, Sijie; De Pontieu, Bart +2 more
We report on observations of highly-varying Si IV 1402.77 Å line profiles observed with the Interface Region Imaging Spectrograph (IRIS) during the M-class flare from 2022 January 18 at an unprecedented 0.8 s cadence. Moment analysis of this line observed in flare ribbon kernels showed that the intensity, Doppler velocity, and non-thermal broadeni…
Subarcsecond Imaging of a Solar Active Region Filament With ALMA and IRIS
Heinzel, P.; Gunár, S.; Leenaarts, J. +4 more
Quiescent filaments appear as absorption features on the solar disk when observed in chromospheric lines and at continuum wavelengths in the millimeter (mm) range. Active region (AR) filaments are their small-scale, low-altitude analogues, but they could not be resolved in previous mm observations. This spectral diagnostic can provide insight into…
The quiet sun at mm wavelengths as seen by ALMA
Brajša, Roman; Bastian, T. S.; Alissandrakis, Costas E.
Solar observations at sub-mm, mm and cm wavelengths offer a straightforward diagnostic of physical conditions in the solar atmosphere because they yield measurement of brightness temperature which, for optically thick features, equals intrinsic temperature - much unlike solar diagnostics in other spectral ranges. The Atacama Large Millimeter and s…
A window into magnetic reconnection: IRIS observations of the consequences of reconnection during solar flares
Reeves, Katharine K.
Magnetic reconnection is a dynamic process that occurs in solar flares in a tenuous and hot environment. High-cadence, high-spatial resolution spectroscopic observations with the Interface Region Imaging Spectrometer (IRIS) have provided a unique window into the reconnection process that occurs during solar flares. IRIS has observed many consequen…
Interface Region Imaging Spectrograph (IRIS) Observations of the Fractal Dimension in the Solar Atmosphere
Aschwanden, Markus J.; Vilangot Nhalil, Nived
While previous work explored the fractality and self-organized criticality (SOC) of flares and nanoflares in wavelengths emitted in the solar corona (such as in hard X-rays, soft X-rays, and EUV wavelenghts), we focus here on impulsive phenomena in the photosphere and transition region, as observed with the {\sl Interface Region Imaging Spectrogra…