Found 62 talks archived in Particle astrophysics, physical data and processes
A continuous magnetic field evolving under the hydromagnetic frozen-in condition preserves its field topology. Depending on that field topology, the evolving field may inevitably develop electric current-sheets, i.e., magnetic tangential discontinuities, in the course of nonlinear fluid-field interaction. This inevitability obtains for all field topologies one could prescribe for the field, except those of a special subset of measure zero. This theory of Eugene Parker is based on demonstrating that a field endowed with a fixed topology cannot generally find an equilibrium state in which the field is everywhere spatially continuous. I will discuss a recent development of this magnetostatic problem from an intuitive point of view, giving a basic understanding of why current sheets not only form easily but do so throughout a magnetic field. Parker’s theory explains the heating of the solar corona, to million-degree temperatures, in terms of spontaneous current sheets that must form because of high electrical conductivity, and, yet, must dissipate in spite of that high (but finite) conductivity. This process may be the fundamental reason for the high-temperature plasmas found almost everywhere in the astrophysical universe
AbstractIn the EU funded Marie Curie Excellence Team CIFIST (Cosmological Impact of the FIrst STars) work is under way to construct 3D radiation-hydrodynamical model atmospheres for late-type dwarfs and giants, in particular of low metallicity. I will present an overview of the present state of the efforts, discuss some applications of the models, and point to necessary future developments.
- Temperature inhomogeneities cause the abundance discrepancy in H II regionsDr. J. Eduardo Méndez-DelgadoTuesday June 13, 2023 - 12:30 GMT+1 (Aula)
- TBDDr. Doug RennehanThursday June 15, 2023 - 10:30 GMT+1 (Aula)