Plasma propulsion simulation using particles

This perspective paper deals with an overview of particle-in-cell / Monte Carlo collision models applied to different plasma-propulsion configurations and scenarios, from electrostatic (E x B and pulsed arc) devices to electromagnetic (RF inductive, helicon, electron cyclotron resonance) thrusters, with an emphasis on plasma plumes and their interaction with the satellite. The most important elements related to the modeling of plasma-wall interaction are also presented. Finally, the paper reports new progress in the particle-in-cell computational methodology, in particular regarding accelerating computational techniques for multi-dimensional simulations and plasma chemistry Monte Carlo modules for molecular and alternative propellan

Modeling of the negative ion source and accelerator of the ITER Neutral Beam Injector

This manuscript compiles about 10 years of research on the modelling of the negative ion source and the accelerator of the ITER Neutral Beam Injector. ITER is the next generation Tokamak for fusion applications. This work is essentially theoretical and numerical but comparison with experiments is performed as frequently as possible based on available data. The background physics and numerical techniques are described in details. This work is consequently accessible to a person without a large knowledge on the physics of negative ion sources or ion accelerators

Production of negative hydrogen ions in a magnetized plasma column

International audienceA new generation of neutral beam systems will be required in future fusion reactors, such as DEMO, able to deliver high power (up to 50 MW) with high neutral energy (\textgreater 1 MeV). Negative ions have a higher neutralization fraction (compared to positive ions) in a gas cell at energies greater than 50 keV. They are generated mostly on cesiated metal surfaces inside a magnetized high brightness plasma source but cesium consumption must be limited to a minimum in a fusion power plant to reduce the maintenance of the source. There is hence a strong research focus to optimize the production of negative ions via dissociative attachment of the gas molecule inside the source volume. To achieve this, one must generate a plasma with a hot (\textasciitilde 10 eV) and cold (\textasciitilde 1 eV) electron temperature regions and confine the electrons magnetically. In this work, we will analyse the properties of a hydrogen plasma produced in a thin (20 cm radius and 1.8 m length) magnetized (\textasciitilde 150G) plasma column powered by a helicon discharge [I. Furno et al., EPJ Web of Conferences \textbf{157}, 03014 (2017)]. The numerical simulations are performed with a 2.5D Particle-in-Cell algorithm with Monte-Carlo Collisions (PIC-MCC) [G. Fubiani et al., New J. Phys. \textbf{19}, 015002 (2017)]. The model will be compared to experiments. *Work carried out within the framework of the EUROfusion Consortium. Euratom Grant Agreement No. 633053

E × B electron drift current across the aperture of an ion source surrounded by a cusped magnetic field profile

International audienceIn negative ion sources, a cusped magnetic field is generated by magnets placed around each aperture of the extraction grid in order to limit the co-extracted electron current. In spite of this suppression magnetic field, the co-extracted electron current is large, on the same order as the negative ion current extracted from the plasma. In this paper, we study the mechanisms of electron extraction from the plasma through a cusped aperture in a simplified situation, in the absence of negative ions, with the help of a three-dimensional Particle-In-Cell Monte Carlo Collisions model. The calculation results show that the electron current extracted from the plasma is small for an infinite slit aperture with a suppressed (cusped) magnetic field and significantly increases in the case of finite slit or circular grid apertures. We find that the E Â B electron drift plays an important role in the extraction of electrons through a finite slit grid aperture and that current driven micro instabilities are present in the aperture region. This work is relevant to negative ion sources and micro-ECR neutralizers designed for space propulsion