arXiv subjects

Renaud Gueroult

Publications and source records attributed to Renaud Gueroult.

24 records · Page 2Linked to original sources

arXiv2017

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.

physics.plasm-ph↗

arXiv2017

Centrifugal instability in the regime of fast rotation

Centrifugal instability, which stems from a difference between the azimuthal angular drift velocity of ions and electrons, is studied in the limit of fast rotation for which ions can rotate up to twice as fast as electrons. As the angular velocity approaches the so-called Brillouin limit, the growth rate for the centrifugal instability in a collisionless solid-body rotating plasma increases markedly, and is proportional to the azimuthal mode number. For large wavenumbers, electron inertia effects set in and lead to a cut-off. Interestingly, conditions for the onset of this instability appear to overlap with the operating conditions envisioned for plasma mass separation devices.

physics.plasm-ph↗

arXiv2017

Harnessing mass differential confinement effects in magnetized rotating plasmas to address new separation needs

The ability to separate large volumes of mixed species based on atomic mass appears desirable for a variety of emerging applications with high societal impact. One possibility to meet this objective consists in leveraging mass differential effects in rotating plasmas. Beyond conventional centrifugation, rotating plasmas offer in principle additional ways to separate elements based on mass. Single ion orbits show that ion radial mass separation in a uniform magnetized plasma column can be achieved by applying a tailored electric potential profile across the column, or by driving a rotating magnetic field within the column. Furthermore, magnetic pressure and centrifugal effects can be combined in a non-uniform geometry to separate ions based on mass along the field lines. Practical application of these separation schemes hinges on the ability to produce the desirable electric and magnetic field configuration within the plasma column.

physics.plasm-ph↗

arXiv2017

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.

physics.plasm-ph↗

arXiv2016

Practicality of magnetic compression for plasma density control

Plasma densification through magnetic compression has been suggested for time-resolved control of the wave properties in plasma-based accelerators. Using particle in cell simulations with real mass ratio, the practicality of large magnetic compression on timescales shorter than the ion gyro-period is investigated. For compression times shorter than the transit time of a compressional Alfven wave across the plasma slab, results show the formation of two counter-propagating shock waves, leading to a highly non-uniform plasma density profile. Furthermore, the plasma slab displays large hydromagnetic like oscillations after the driving field has reached steady state. Peak compression is obtained when the two shocks collide in the mid-plane. At this instant, very large plasma heating is observed, and plasma $β$ is estimated to be about $1$. Although these results point out a densification mechanism quite different and more complex than initially envisioned, these features could possibly be advantageous in particle accelerators.

physics.plasm-ph↗

arXiv2015

Plasma filtering techniques for nuclear waste remediation

Nuclear waste cleanup is challenged by the handling of feed stocks that are both unknown and complex. Plasma filtering, operating on dissociated elements, offers advantages over chemical methods in processing such wastes. The costs incurred by plasma mass filtering for nuclear waste pretreatment, before ultimate disposal, are similar to those for chemical pretreatment. However, significant savings might be achieved in minimizing the waste mass. This advantage may be realized over a large range of chemical waste compositions, thereby addressing the heterogeneity of legacy nuclear waste.

physics.plasm-ph↗