caa a22 4500 445346299 CHVBK 20180317142830.0 cr unu---uuuuu 170323e20110801xx s 000 0 eng 10.1007/s11207-011-9795-5 doi (NATIONALLICENCE)springer-10.1007/s11207-011-9795-5 Damping of Longitudinal Magneto-Acoustic Oscillations in Slowly Varying Coronal Plasma [Elektronische Daten] [R. Erdélyi, K. Al-Ghafri, R. Morton] We investigate the propagation of MHD waves in a magnetised plasma in a weakly stratified atmosphere, representative of hot coronal loops. In most earlier studies, a time-independent equilibrium was considered. Here we abandon this restriction and allow the equilibrium to develop as a function of time. In particular, the background plasma is assumed to be cooling due to thermal conduction. The cooling is assumed to occur on a time scale greater than the characteristic travel times of the perturbations. We investigate the influence of cooling of the background plasma on the properties of magneto-acoustic waves. The MHD equations are reduced to a 1D system modelling magneto-acoustic modes propagating along a dynamically cooling coronal loop. A time-dependent dispersion relation that describes the propagation of the magneto-acoustic waves is derived using the WKB theory. An analytic solution for the time-dependent amplitude of waves is obtained, and the method of characteristics is used to find an approximate analytical solution. Numerical calculations of the analytically derived solutions are obtained to give further insight into the behaviour of the MHD waves in a system with a variable, time-dependent background. The results show that there is a strong damping of MHD waves and the damping also appears to be independent of the position along the loop. Studies of MHD wave behaviour in a time-dependent backgrounds seem to be a fundamental and very important next step in the development of MHD wave theory that is applicable to a wide range of situations in solar physics. Springer Science+Business Media B.V., 2011 Magnetohydrodynamics (MHD) nationallicence Plasmas nationallicence Sun: corona nationallicence Waves nationallicence Erdélyi R. Solar Physics and Space Plasma Research Centre (SP²RC), University of Sheffield, Hicks Building, Hounsfield Road, S3 7RH, Sheffield, UK aut Al-Ghafri K. Solar Physics and Space Plasma Research Centre (SP²RC), University of Sheffield, Hicks Building, Hounsfield Road, S3 7RH, Sheffield, UK aut Morton R. Solar Physics and Space Plasma Research Centre (SP²RC), University of Sheffield, Hicks Building, Hounsfield Road, S3 7RH, Sheffield, UK aut Solar Physics Springer Netherlands 272/1(2011-08-01), 73-89 0038-0938 272:1<73 2011 272 11207 https://doi.org/10.1007/s11207-011-9795-5 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11207-011-9795-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Erdélyi R. Solar Physics and Space Plasma Research Centre (SP²RC), University of Sheffield, Hicks Building, Hounsfield Road, S3 7RH, Sheffield, UK aut NATIONALLICENCE 700 1- Al-Ghafri K. Solar Physics and Space Plasma Research Centre (SP²RC), University of Sheffield, Hicks Building, Hounsfield Road, S3 7RH, Sheffield, UK aut NATIONALLICENCE 700 1- Morton R. Solar Physics and Space Plasma Research Centre (SP²RC), University of Sheffield, Hicks Building, Hounsfield Road, S3 7RH, Sheffield, UK aut NATIONALLICENCE 773 0- Solar Physics Springer Netherlands 272/1(2011-08-01), 73-89 0038-0938 272:1<73 2011 272 11207 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer