2020/07/14 by Barnali Das, Surajit Mondal, Das, Barnali +3 · 2 citations
Engineering · Physics and Astronomy · #FOS: Physical sciences #Ionosphere and magnetosphere dynamics #Magnetic confinement fusion research #Particle accelerators and beam dynamics #Solar and Stellar Astrophysics (astro-ph.SR)
paper · pdf · doi:10.48550/arxiv.2007.06822
openalex publication_date 2020/07/14 · openalex created_date 2022/07/23 · openalex updated_date 2026/07/28
Recently, coherent radio emission has been discovered from a number of hot\nmagnetic stars, via the process of electron cyclotron maser emission (ECME).\nThis emission, observed in the form of highly circularly polarized pulses, have\ninteresting properties which contain information about the host star. One of\nthe important properties of ECME is the frequency dependence of the pulse\narrival time. This has been attributed to propagation effect by Trigilio et al.\n(2011), and could explain the sequence observed for CU Vir qualitatively (Lo et\nal. 2012). However no quantitative treatment exists for this phenomenon which\nis a promising tool to estimate the density in the stellar magnetosphere.\nBesides, the effect of propagation through the magnetosphere on ECME has been\nthought to be limited to giving rise to a particular sequence of arrival of\npulses, and in some cases producing the upper cut-off frequency for ECME (Leto\net al. 2019). Here, we present a framework to deal with the propagation effect\nby considering continuous refraction in the inner magnetosphere of the star.\nThis framework is capable of incorporating any type of density distribution,\nand in principle any type of magnetic field, though we limit ourselves to a\ndipolar magnetic field for this work. We show by simulation that for stars with\nhigh obliquity, the propagation effect can influence not only the sequence of\narrival of pulses drastically, but also the pulse shapes, and the observability\nof a pulse from a particular magnetosphere.\n