In this perspective paper, we critically analyse the state-of-the-art of arc discharge technique of carbon nanoparticle synthesis. We discuss improving controllability of the arc discharge synthesis of carbon nanotubes, synthesis of graphene as well as general understanding of the synthesis process. Fundamental issues related to relationship between plasma parameters and carbon nanostructure characteristics are considered. Effects of electrical and magnetic fields applied during single-wall carbon nanotube synthesis in arc plasma are explored. Finally our personal opinion on what future trends will be in arc discharge synthesis is offered.

For the past four years, the Micropropulsion and Nanotechnology Laboratory at the George Washington University has been developing a novel thruster for microsatellites based on an ablative vacuum arc technology, so called micro-cathode arc thruster (µCAT). Ablative microthrusters, such as the µCAT, offer a number of advantages for small satellite missions, especially ones utilizing the CubeSat technology. However, before the thruster can be operated in the space environment, it is necessary to obtain a better understanding of its performance, plume profile, and any potential adverse effects to the host spacecraft. Complicating data collection is the miniature size of the device, which reduces the usefulness of traditional probing methods. In this paper we report on an on-going numerical analysis performed in support of the experimental characterization of the thruster. Namely, we investigate the formation of the discharge beam from the initial cathode spot under an applied magnetic field.

This paper describes a further development and characterization of vacuum arc thruster with external magnetic field. The velocity of ions moving from the micro-Cathode Arc Thrusters (µCAT) cathode spots was measured using a set of grid probes along the path of the plasma plume expansion. The goal was to get the ion drift velocity and determine how much, if any, change of ion drift velocity occurs in the expanded plasma propagation path. It was found the ion drift velocity was increased when magnetic field increased (from 0 up to 200mT). The average ion velocity (cathode material is Ti) increases by factor of 2-3 up to about (3-4) × 10 4 m s −1 with magnetic field strength 200mT applied. Rotation of cathode spot as a result of an applied magnetic field is demonstrated by using Langmuir probes inserted inside the source channel azimuthally. Ion current distribution outside the thruster channel was measured using a set of special assemble of concentric circles plan probe alone the plasma propagation path. It is shown that plasma generated at the cathode spot is guided along the magnetic field line.