Search results for "Magnetohydrodynamics"
showing 6 items of 206 documents
Numerical treatment of radiation processes in the internal shocks of magnetized relativistic outflows
2017
Los blázares son un tipo de núcleo activo de galaxia (AGN, por sus siglas en inglés) que se encuentran entre los objetos astrofísicos más energéticos y violentos, a la par de los brotes de rayos gamma (GRB por sus siglas en inglés). Los procesos físicos y, en particular, el escenario del chorro relativista en el que se genera la radiación ultraenergética detectada por observatorios terrestres y en órbita, han conseguido atraer la atención e interés de los astrónomos y astrofísicos desde su descubrimiento. En la presente tesis investigamos el modelo de choques internos (IS) cuya hipótesis consta del choque de dos capas de plasma con geometría cilíndrica, formando dos ondas de choque que atra…
Study of thermoelectric magnetohydrodynamic convection on solute redistribution during laser additive manufacturing
2020
Abstract Melt pools formed in laser additive manufacturing (AM) are subject to large thermal gradients, resulting in the formation of thermoelectric currents due to the Seebeck effect. When in the presence of an external magnetic field, a Lorentz force is formed which drives fluid flow in the melt pool. This Thermoelectric Magnetohydrodynamics (TEMHD) phenomenon, can have a significant impact on the melt pool morphology and can alter the microstructural evolution of the solidification process. By coupling steady-state mesoscopic melt pool calculations to a microscopic solidification model, predictions of the resulting microstructure for multiple deposited layers have been obtained. The resu…
Three-dimensional core-collapse supernovae with complex magnetic structures: I. Explosion dynamics
2021
Magnetic fields can play a major role in the dynamics of outstanding explosions associated to violent events such as GRBs and hypernovae, since they provide a natural mechanism to harness the rotational energy of the central proto-neutron star and power relativistic jets through the stellar progenitor. As the structure of such fields is quite uncertain, most numerical models of MHD-driven core-collapse supernovae consider an aligned dipole as initial magnetic field, while the field's morphology can actually be much more complex. We present three-dimensional simulations of core-collapse supernovae with more realistic magnetic structures, such as quadrupolar fields and, for the first time, an…
The impact of non-dipolar magnetic fields in core-collapse supernovae
2019
The magnetic field is believed to play an important role in at least some core-collapse supernovae if its magnitude reaches $10^{15}\,\rm{G}$, which is a typical value for a magnetar. In the presence of fast rotation, such a strong magnetic field can drive powerful jet-like explosions if it has the large-scale coherence of a dipole. The topology of the magnetic field is, however, probably much more complex with strong multipolar and small-scale components and the consequences for the explosion are so far unclear. We investigate the effects of the magnetic field topology on the dynamics of core-collapse supernovae and the properties of forming proto-neutron star (PNS) by comparing pre-collap…