Related papers: The Role of Type II Spicules in the Upper Solar At…
All but the most massive main-sequence stars are expected to have a rarefied and hot (million-Kelvin) corona like the Sun. How such a hot corona is formed and supported has not been completely understood yet, even in the case of the Sun.…
In addition to a component of the emission that originates from clearly distinguishable coronal loops, the solar corona also exhibits extreme-ultraviolet (EUV) and X-ray ambient emission that is rather diffuse and is often considered…
Understanding the dynamic solar chromosphere is fundamental in solar physics. Spicules are an important feature of the chromosphere, connecting the photosphere to the corona, potentially mediating the transfer of energy and mass. The aim of…
We report observations of solar spicules at millimeter wavelengths (mm-$\lambda$) using the Atacama Large Millimeter/submillimeter Array (ALMA). These are supplemented by observations in optical (O), ultraviolet (UV) and extreme ultraviolet…
Solar corona is much hotter than lower layers of the solar atmosphere-photosphere and chromosphere. The coronal temperature is up to 1MK in quiet sun areas, while up to several MK in active regions, which implies a key role of magnetic…
High resolution spectra from the Hinode EUV Imaging Spectrometer (EIS) have revealed that coronal spectral line profiles are sometimes asymmetric, with a faint enhancement in the blue wing on the order of 100 km/s. These asymmetries could…
The profiles of emission lines formed in the corona contain information on the dynamics and the heating of the hot plasma. Only recently has data with sufficiently high spectral resolution become available for investigating the details of…
The solar corona, the tenuous outer atmosphere of the Sun, is orders of magnitude hotter than the solar surface. This 'coronal heating problem' requires the identification of a heat source to balance losses due to thermal conduction,…
We study the line profiles of a range of transition region (TR) emission lines observed in typical quiet Sun regions. In magnetic network regions, the Si IV 1402\AA{}, C IV 1548\AA{}, N V 1238\AA{}, O VI 1031\AA{}, and Ne VIII 770\AA{}…
EUV observations of warm coronal loops suggest that they are bundles of unresolved strands that are heated impulsively to high temperatures by nanoflares. The plasma would then have the observed properties (e.g., excess density compared to…
Condensations in the more than 10^6 K hot corona of the Sun are commonly observed in the extreme ultraviolet (EUV). While their contribution to the total solar EUV radiation is still a matter of debate, these condensations certainly provide…
We performed a 3D radiative MHD simulation of the solar atmosphere. This simulation shows a jet-like feature that shows similarities to the type II spicules observed for the first time with Hinode. Rapid Blueshifted Events (RBEs) on the…
have forced the definition of a new type of spicule, "type II's", that are characterized by rising rapidly, having short lives, and by fading away at the end of their lifetimes. Here, we report on features found in realistic 3D simulations…
The Sun's chromosphere is a critical region to understand when considering energy and mass deposition into the transition region and corona, but many of the smaller, faster events which transport a portion of this mass and energy are still…
Low-frequency turbulence in the solar chromosphere remains poorly understood. We address 1) the sources of low-frequency turbulence that potentially heat the chromosphere, and 2) how turbulence is transported and dissipated throughout the…
Recent solar spectroscopic observations have shown that coronal spectral lines can exhibit asymmetric profiles, with enhanced emissions at their blue wings. These asymmetries correspond to rapidly upflowing plasmas at speeds exceeding ~ 50…
Spicules are long, thin, highly dynamic features that jut out ubiquitously from the solar limb. They dominate the interface between the chromosphere and corona and may provide significant mass and energy to the corona. We use high-quality…
In many astrophysical systems, mixing between cool and hot temperature gas/plasma through Kelvin-Helmholtz-instability-driven turbulence leads to the formation of an intermediate temperature phase with increased radiative losses that drive…
Why the tenuous solar outer atmosphere, or corona, is much hotter than the underlying layers remains one of the greatest challenge for solar modeling. Detailed diagnostics of the coronal thermal structure come from extreme ultraviolet (EUV)…
The solar corona is much hotter than the photosphere and chromosphere, but the physical mechanism responsible for heating the coronal plasma remains unidentified yet. The thermal microwave emission, which is produced in strong magnetic…