  Extensive particle-in-cell simulations of fast electron beams injected in a
background magnetised plasma with a decreasing density profile 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 [D. Tsiklauri, Phys. Plasmas, 18, 052903 (2011)]. The numerical
simulations were carried out using different density profiles and fast electron
distribution functions. It is shown that electromagnetic L and R modes are
excited by the transverse current, initially imposed on the system. In the
course of the simulations no further interaction of the electron beam with the
background plasma could be observed.
