Effect of Synthesis Techniques on the Optical Properties of Ho 3+ /Yb 3+ Co-doped YVO 4 Phosphor: A Comparative Study

Abstract

In this study, we present the observations of extreme-ultraviolet (EUV) waves associated with an M6.5 flare on 2013 April 11. The event was observed by Solar Dynamics Observatory (SDO) in different EUV channels. The flare was also associated with a halo CME and type II radio bursts. We observed both fast and slow components of the EUV wave. The speed of the fast component, which is identified as a fast-mode MHD wave, varies in the range from 600 to 640kms−1, whereas the speed of the slow-component is ≈140kms−1. We observed the unusual phenomenon that, as the fast-component EUV wave passes through two successive magnetic quasi-separatrix layers (QSLs), two stationary wave fronts are formed locally. We propose that part of the outward-propagating fast-mode EUV wave is converted into slow-mode magnetohydrodynamic waves, which are trapped in local magnetic field structures, forming successive stationary fronts. Along the other direction, the fast-component EUV wave also creates oscillations in a coronal loop lying ≈225Mm away from the flare site. We have computed the energy of the EUV wave to be of the order of 1020J. © 2019, Springer Nature B.V.