Coronal holes are the darkest and least active regions of the Sun, as observed both on the
solar disk and above the solar limb. Coronal holes are associated with rapidly expanding …

The discovery of exoplanets and the desire to understand their atmospheric chemical
composition and habitability provides a new rationale for understanding the radiation from X …

Semiempirical atmospheric models of solar surface features as observed at moderate
resolution are useful tools for understanding the observed solar spectral irradiance …

A magnetic field modifies the properties of waves in a complex way. Significant advances
have been made recently in our understanding of the physics of sunspot waves with the help …

ABSTRACT A big challenge in solar and stellar physics in the coming years will be to
decipher the magnetism of the solar outer atmosphere (chromosphere and corona) along …

Magnetic fields on the surface of the Sun and stars in general imprint or modify the
polarization state of the electromagnetic radiation that is leaving from the star. The inference …

While solar flares are predominantly characterized by an intense broadband enhancement
to the solar radiative output, certain spectral lines and continua will, in theory, exhibit flare …

We analyze the propagation of waves in sunspots from the photosphere to the
chromosphere using time series of co-spatial Ca ii H intensity spectra (including its line …

Velocity oscillations" measured" simultaneously at the photosphere and the chromosphere—
from time series of spectropolarimetric data in the 10830 Å region—of different solar …

Helium ionization plays an important role in the energy balance of the upper chromosphere
and transition region. Helium spectral lines are also often used as diagnostics of these …