On the role of magnetosonic solitons in perpendicular collisionless shock reformation

The nature of the magnetic structure arising from ion specular reflection in shock compression studies is examined by means of 1d particle in cell simulations. Propagation speed, field profiles and supporting currents for this magnetic structure are shown to be consistent with a magnetosonic soliton. Coincidentally, this structure and its evolution are typical of foot structures observed in perpendicular shock reformation. To reconcile these two observations, we propose, for the first time, that shock reformation can be explained as the result of the formation, growth and subsequent transition to a super-critical shock of a magnetosonic soliton. This argument is further supported by the remarkable agreement found between the period of the soliton evolution cycle and classical reformation results. This new result suggests that the unique properties of solitons can be used to shed new light on the long-standing issue of shock non-stationarity and its role on particle acceleration.Comment: Accepted for publication in Physical Review Letter

Opportunities for plasma separation techniques in rare earth elements recycling

Rare earth elements recycling has been proposed to alleviate supply risks and market volatility. In this context, the potential of a new recycling pathway, namely plasma mass separation, is uncovered through the example of nedodymium - iron - boron magnets recycling. Plasma mass separation is shown to address some of the shortcomings of existing rare earth elements recycling pathways, in particular detrimental environmental effects. A simplified mass separation model suggests that plasma separation performances could compare favourably with existing recycling options. In addition, simple energetic considerations of plasma processing suggest that the cost of these techniques may not be prohibitive, particularly considering that energy costs from solar may become significantly cheaper. Further investigation and experimental demonstration of plasma separation techniques should permit asserting the potential of these techniques against other recycling techniques currently under development.Comment: Submitted to Journal of Cleaner Productio

Contribution of fictitious forces to polarization drag in rotating media

Models for polarization drag - mechanical analog of the Faraday effect - are extended to include inertial corrections to the dielectrics properties of the rotating medium in its rest-frame. Instead of the Coriolis-Faraday term originally proposed by Baranova & Zel'dovich, inertia corrections due to the fictitious Coriolis and centrifugal forces are here derived by considering the effect of rotation on both the Lorentz and plasma dielectric models. These modified rest-frame properties are subsequently used to deduce laboratory properties. Although elegant and insightful, it is shown that the Coriolis-Faraday correction inferred from Larmor's theorem is limited in that it can only capture inertial corrections to polarization drag when the equivalent Faraday rotation is defined at the wave frequency of interest. This is notably not the case for low frequency polarization drag in a rotating magnetized plasma, although it is verified here using the more general phenomenological models that the impact of fictitious forces is in general negligible in these conditions.Comment: 10 pages, 4 figure