Electromagnetic Transparency in strongly magnetized plasmas

Plasma being a collection of charged particles interacts with Electromagnetic fields and can display wide ranging of scattering, absorption, reflection and transmission of the wave. It is shown here with the help of PIC simulations, that a plane laser pulse is able to propagate unhindered inside the plasma in the presence of a very strong magnetic field. The study has been conducted for a configuration for which the applied external magnetic field is normal to the laser electric field. The applied magnetic field is strong to magnetize even the heavier ion species. The plasma in this case behaves like a vacuum for the propagation of the EM field. The phenomena is understood by realising that when the applied magnetic field is strong, the resonance and cut-off points approach each other, and as a result, the width of stop-band gets reduced. Thus, the EM wave is allowed to propagate inside the medium. In this case, even though charges move, there is no current generated in the medium, nor does any charge separation occurs. Thus, the source in the Maxwells equation which alters the vacuum dielectric behaviour is totally absent. This study is relevant in astrophysical scenario where plasmas are often threaded with strong magnetic fields.