Related papers: The Role of Partial Ionization Effects in the Chro…
Low-metallicity environments are subject to inefficient cooling. They also have low dust-to-gas ratios and therefore less efficient photoelectric (PE) heating than in solar-neighbourhood conditions, where PE heating is one of the most…
Understanding the evolution of the complex magnetic fields found in solar active regions is an active area of research. There are numerous models for such fields which range in their complexity due to the number of known physical effects…
The solar wind emanates from the hot and tenuous solar corona. Earlier studies using 1.5 dimensional simulations show that Alfv\'{e}n waves generated in the photosphere play an important role in coronal heating through the process of…
We show that multiply ionized coronal C, N, O, Mg, Si, S ions carried by the solar wind and neutralized by consecutive electron captures from neutral interstellar atoms constitute an important new source of neutral atoms in the inner…
Pickup ions are created when interstellar neutral atoms resonantly exchange charge with the solar wind (SW) ions, especially in the supersonic part of the wind, where they carry most of the plasma pressure. Here we present numerical…
Aims: To investigate magnetic reconnection rates during the coalescence of two current loops in the solar chromosphere, by altering the neutral-hydrogen to proton density ratio, ioniziation/recombination coefficients, collision frequency…
In the present work we use a deep-exposure spectrum taken by the SUMER spectrometer in a polar coronal hole in 1996 to measure the ion temperatures of a large number of ions at many different heights above the limb between 0.03 and 0.17…
The Sun's outer atmosphere, the corona, is maintained at mega-Kelvin temperatures and fills the heliosphere with a supersonic outflowing wind. The dissipation of magnetic waves and direct electric currents are likely to be the most…
High-energy particles enter the solar atmosphere from Galactic or solar coronal sources, producing an "albedo'' source from the quiet Sun, now observable across a wide range of photon energies. The interaction of high-energy particles in a…
We investigate the morphology and temporal variability of a quiet Sun network region in different solar layers. The emission in several EUV spectral lines through both raster and slot time series, recorded by EIS/Hinode is studied along…
It is widely believed that the heating of the chromosphere in quiet-Sun internetwork regions is provided by dissipation of acoustic waves that are excited by the convective motions close to the top of the convection zone and in the…
The ionizing background determines the ionization balance and the thermodynamics of the cosmic gas. It is therefore a fundamental ingredient to theoretical and empirical studies of both the IGM and galaxy formation. We present here a new…
Solar flares are driven by the release of magnetic energy from reconnection events in the solar corona, whereafter energy is transported to the chromosphere, heating the plasma and causing the characteristic radiative losses. In the…
In this paper we have extended our previous modeling of energy balance in the chromosphere-corona transition region to cases with particle and mass flows. The cases considered here are quasi-steady, and satisfy the momentum and energy…
The solar atmosphere is composed of many species which are populated at different ionization and excitation levels. The upper chromosphere, transition region, and corona are nearly collisionless. Consequently, slippage between, for…
It is extremely difficult to simulate the details of coronal heating and also make meaningful predictions of the emitted radiation. Thus, testing realistic models with observations is a major challenge. Observational signatures of coronal…
In this paper we study the role of radiative cooling in a two-fluid model consisting of coupled neutrals and charged particles. We first analyze the linearized two-fluid equations where we include radiative losses in the energy equation for…
We present a new computational approach that addresses the difficulty of obtaining the correct interaction between the solar corona and the transition region in response to rapid heating events. In the coupled corona, transition region and…
The solar atmosphere is dominated by loops of magnetic flux which connect the multi-million-degree corona to the much cooler chromosphere. The temperature and density structure of quasi-static loops is determined by the continuous flow of…
When magnetic field in the solar convection zone buoyantly rises to pierce the visible solar surface (photosphere), the atmosphere (corona) above this surface must respond in some way. One response of the coronal field to photospheric…