Bibcode
Popescu Braileanu, B.; Lukin, V. S.; Khomenko, E.; de Vicente, Á.
Bibliographical reference
Astronomy and Astrophysics, Volume 627, id.A25, 18 pp.
Advertised on:
7
2019
Journal
Citations
49
Refereed citations
48
Description
Solar chromosphere consists of a partially ionized plasma, which makes
modeling the solar chromosphere a particularly challenging numerical
task. Here we numerically model chromospheric waves using a two-fluid
approach with a newly developed numerical code. The code solves
two-fluid equations of conservation of mass, momentum, and energy,
together with the induction equation for the case of the purely hydrogen
plasma with collisional coupling between the charged and neutral fluid
components. The implementation of a semi-implicit algorithm allows us to
overcome the numerical stability constraints due to the stiff
collisional terms. We test the code against analytical solutions of
acoustic and Alfvén wave propagation in uniform medium in several
regimes of collisional coupling. The results of our simulations are
consistent with the analytical estimates, and with other results
described in the literature. In the limit of a large collisional
frequency, the waves propagate with a common speed of a single fluid. In
the other limit of a vanishingly small collisional frequency, the
Alfvén waves propagate with an Alfvén speed of the charged
fluid only, while the perturbation in neutral fluid is very small. The
acoustic waves in these limits propagate with the sound speed
corresponding to either the charges or the neutrals, while the
perturbation in the other fluid component is negligible. Otherwise, when
the collision frequency is similar to the real part of the wave
frequency, the interaction between charges and neutrals through
momentum-transfer collisions cause alterations of the waves frequencies
and damping of the wave amplitudes.
Related projects
Numerical Simulation of Astrophysical Processes
Numerical simulation through complex computer codes has been a fundamental tool in physics and technology research for decades. The rapid growth of computing capabilities, coupled with significant advances in numerical mathematics, has made this branch of research accessible to medium-sized research centers, bridging the gap between theoretical and
Daniel Elías
Nóbrega Siverio
Solar and Stellar Magnetism
Magnetic fields are at the base of star formation and stellar structure and evolution. When stars are born, magnetic fields brake the rotation during the collapse of the mollecular cloud. In the end of the life of a star, magnetic fields can play a key role in the form of the strong winds that lead to the last stages of stellar evolution. During
Tobías
Felipe García
Magnetism, Polarization and Radiative Transfer in Astrophysics
Magnetic fields pervade all astrophysical plasmas and govern most of the variability in the Universe at intermediate time scales. They are present in stars across the whole Hertzsprung-Russell diagram, in galaxies, and even perhaps in the intergalactic medium. Polarized light provides the most reliable source of information at our disposal for the
Tanausú del
Pino Alemán