Related papers: Self-absorption in the solar transition region
Recent observations by the Interface Region Imaging Spectrograph (IRIS) have revealed pockets of hot gas ($\sim$2--8$\times$10$^{4}$ K) potentially resulting from magnetic reconnection in the partially ionized lower solar atmosphere (IRIS…
Solar ultraviolet (UV) bursts are small-scale compact brightenings in transition region images. The spectral profiles of transition region lines in these bursts are significantly enhanced and broadened, often with chromospheric absorption…
Many models for coronal loops have difficulty explaining the observed EUV brightness of the transition region, which is often significantly less than theoretical models predict. This discrepancy has been addressed by a variety of approaches…
The origin of nonthermal broadening in solar spectra is one of the long-standing questions in solar physics. Various processes have been invoked - including unresolved flows, waves, and turbulent processes - but definitive answers are…
Coronal bright points (BPs) are small-scale luminous features seen in the solar corona. Quasi-periodic brightenings are frequently observed in the BPs and are generally linked with underneath magnetic flux changes. We study the dynamics of…
Small-scale brightenigs are ubiquitous, dynamic and energetic phenomena found in the chromopshere. An advanced filter-detection algorithm applied to high-resolution observations from the Interface Region Imaging Spectrograph enables the…
The heating of the outer solar atmospheric layers, i.e., the transition region and corona, to high temperatures is a long standing problem in solar (and stellar) physics. Solutions have been hampered by an incomplete understanding of the…
We use high-resolution imaging spectroscopy with the Swedish 1-m Solar Telescope (SST) to study the transient brightenings of the wings of the Balmer Halpha line in emerging active regions that are called Ellerman bombs. Simultaneous…
Coronal upflows at the edges of active regions (AR), which are a possible source of slow solar wind, have been found to connect with dynamics in the transition region. To infer at what scale transition region dynamics connect to AR upflows,…
The Interface Region Imaging Spectrograph(IRIS) with its high spatial and temporal resolution brings exceptional plasma diagnostics of solar chromospheric and coronal activity during magnetic reconnection. The aim of this work is to study…
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…
The Interface Region Imaging Spectrograph (IRIS) mission provides high-resolution observations of the chromosphere and transition region. We try to determine whether the light walls exist somewhere else in active regions besides light…
Low-lying loops have been discovered at the solar limb in transition region temperatures by the Interface Region Imaging Spectrograph (IRIS). They do not appear to reach coronal temperatures, and it has been suggested that they are the…
The solar atmosphere contains a wide variety of small-scale transient features. Here, we explore the inter-relation between some of them such as surges, explosive events and blinkers via simultaneous spectral and imaging data taken with the…
The solar chromosphere and transition region (TR) form an interface between the Sun's surface and its hot outer atmosphere. Here most of the non-thermal energy that powers the solar atmosphere is transformed into heat, although the detailed…
Localised transient EUV brightenings, sometimes named `campfires', occur throughout the quiet-Sun. However, there are still many open questions about such events, in particular regarding their temperature range and dynamics. In this…
Magnetic reconnection is thought to be a key process in most of solar eruptions. Thanks to high-resolution observations and simulations, the studied scale of reconnection process has become smaller and smaller. Spectroscopic observations…
If gamma-ray bursts are associated with dense star-forming regions in young galaxies, photoelectric absorption by the dense circumburster material (CBM) will occur. As the burst evolves, the surrounding material is photoionized, leading to…
The evolution of the photospheric magnetic field plays a key role in the energy transport into the chromosphere and the corona. In active regions, newly emerging magnetic flux interacts with the pre-existent magnetic field, which can lead…
Spectral lines allow us to probe the thermodynamics of the solar atmosphere, but the shape of a single spectral line may be similar for different thermodynamic solutions. Multiline analyses are therefore crucial, but computationally…