Magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere. Alfvén waves and magneto-sonic waves are particular classes of MHD waves. These wave modes are clearly different and have pure properties in uniform plasmas of infinite extent only. Due to plasma non-uniformity, MHD waves have mixed properties and cannot be classified as pure

El objetivo de esta tesis es el estudio de la estructura magnética de filamentos solares en regiones activas (RAs) y esclarecer su formación y evolución. Mientras que se han observado en numerosas ocasiones (y con diferentes resoluciones espaciales) filamentos fuera de RAs y sobre el limbo solar, el número de observaciones de filamentos en RAs es

A procedure has been developed to compute static aberrations once the telescope PSF has been measured with the lucky imaging technique, using a nearby star close to the object of interest as the point source to probe the optical system. This PSF is iteratively turned into a phase map at the pupil using the Gerchberg-Saxton algorithm and then

Spectral energy distributions (SEDs) of the central few tens of parsecs of some of the nearest active galactic nuclei [AGN] have been used to construct a genuine redshift-zero SED template [1]. This paper presents the comparison between this redshift-zero template and those of the radio loud and radio quiet quasar templates by [2]. Despite the four

We study the modification of the classical criterion for the linear onset and growing rate of the Rayleigh-Taylor instability (RTI) in a partially ionized plasma in the two-fluid description. The plasma is composed of a neutral fluid and an electron-ion fluid, coupled by means of particle collisions. The governing linear equations and appropriate