Lecturer: Dr. David Tsiklauri Affiliation: Queen Mary University of London Abstract: The main unsolved problems in space/solar plasmas will be briefly reviewed, followed by a more detailed discussion of the effect of plasma inhomogeneity on particle acceleration and associated radio emission generation. Extensive particle-in-cell simulations of fast electron beams injected in a background magnetised plasma with a decreasing density profile along the magnetic field were carried out. These simulations were intended to further shed light on a newly proposed mechanism for the generation of electromagnetic waves in type III solar radio bursts [1]. Here recent progress in an alternative to the plasma emission model using Particle-In-Cell, self-consistent electromagnetic wave emission simulations of solar type III radio bursts will be presented. In particular, (i) Fourier space drift (refraction) of non-gyrotropic electron beam-generated wave packets, caused by the density gradient [1,2], (ii) parameter space investigation of numerical runs [3], (iii) concurrent generation of whistler waves [4] and separate problems of (iv) electron acceleration by Langmuir waves in a background magnetised plasma with an increasing density profile along the magnetic field [5] and (v) electron acceleration by dispersive Alfven waves in a plasma with density inhomogeneity across the magnetic field will be presented. In all considered cases the density inhomogeneity-induced wave refraction plays a crucial role. [1] D. Tsiklauri, Phys. Plasmas 18, 052903 (2011) [2] H. Schmitz, D. Tsiklauri, Phys. Plasmas 20, 062903 (2013) [3] R. Pechhacker, D. Tsiklauri, Phys. Plasmas 19, 112903 (2012) [4] M. Skender, D. Tsiklauri, Phys. Plasmas 21, 042904 (2014) [5] R. Pechhacker, D. Tsiklauri, Phys. Plasmas 21, 012903 (2014) [6] D. Tsiklauri, Phys. Plasmas 19, 082903 (2012) Additional details of the upcoming Astrophysics' seminars can be found on the following link. ‏האירוע הזה כולל שיחת וידאו ב-Google Hangouts. הצטרף: https://hangouts.google.com/hangouts/_/mail.huji.ac.il/tba-dr-david?hceid=bWFpbC5odWppLmFjLmlsX2c0czhydDlpcmhwZzRvdGNybWIzZGFqcjdvQGdyb3VwLmNhbGVuZGFyLmdvb2dsZS5jb20.h8kmlog2jeuhh0q4hsojgohnn4&hs=121