We have performed fully-kinetic simulations of X-B and O-X-B mode conversion in one and two dimensional setups using the PIC code EPOCH. We have recovered the linear dispersion relation for electron Bernstein waves by employing relatively low amplitu
de incoming waves. The setups presented here can be used to study non-linear regimes of X-B and O-X-B mode conversion.
Gamma-ray bursts (GRBs) are the most energetic phenomena in the Universe; believed to result from the collapse and subsequent explosion of massive stars. Even though it has profound consequences for our understanding of their nature and selection bia
ses, little is known about the dust properties of the galaxies hosting GRBs. We present analysis of the far-infrared properties of an unbiased sample of 20 textit{BeppoSAX} and textit{Swift} GRB host galaxies (at an average redshift of $z,=,3.1$) located in the {it Herschel} Astrophysical Terahertz Large Area Survey, the {it Herschel} Virgo Cluster Survey, the {it Herschel} Fornax Cluster Survey, the {it Herschel} Stripe 82 Survey and the {it Herschel} Multi-tiered Extragalactic Survey, totalling $880$ deg$^2$, or $sim 3$% of the sky in total. Our sample selection is serendipitous, based only on whether the X-ray position of a GRB lies within a large-scale {it Herschel} survey -- therefore our sample can be considered completely unbiased. Using deep data at wavelengths of 100,--,500$,mu$m, we tentatively detected 1 out of 20 GRB hosts located in these fields. We constrain their dust masses and star formation rates (SFRs), and discuss these in the context of recent measurements of submillimetre galaxies and ultraluminous infrared galaxies. The average far-infrared flux of our sample gives an upper limit on SFR of $<114,{rm M}odot,mbox{yr}^{-1}$. The detection rate of GRB hosts is consistent with that predicted assuming that GRBs trace the cosmic SFR density in an unbiased way, i.e. that the fraction of GRB hosts with $mbox{SFR}>500,{rm M}odot,mbox{yr}^{-1}$ is consistent with the contribution of such luminous galaxies to the cosmic star formation density.
Simulations using 3D and 2D full-wave codes have shown that edge filaments in tokamak plasmas can significantly affect the propagation of microwaves across a broad frequency spectrum, resulting in scattering angles of up to 46 degrees. Parameter scan
s were carried out for density perturbations comparable in width and amplitude to MAST filaments and the effect on the measured emission was calculated. 3D effects were discovered in the case of an obliquely incident beam. In general, the problem of EM propagation past wavelength-sized 3D inhomogeneities is not well understood, yet is of importance for both heating and diagnostic applications in the electron cyclotron frequency range for tokamaks, as well as atmospheric physics. To improve this understanding, a new cold-plasma code, EMIT-3D, was written to extend full-wave microwave simulations in magnetized plasmas to 3D, and make comparisons to the existing 2D code IPF-FDMC. This work supports MAST experiments using the SAMI diagnostic to image microwave emission from the plasma edge due to mode conversion from electron Bernstein waves. Significant fluctuations in the SAMI data mean that detailed modelling is required to improve its interpretation.
