Progress in Development of C$_{60}$ Nanoparticle Plasma Jet for Diagnostic of Runaway Electron Beam-Plasma Interaction and Disruption Mitigation Study for ITER

We produced a C$_{60}$ nanoparticle plasma jet (NPPJ) with uniquely fast response-to-delivery time ($\sim1 - 2$ ms) and unprecedentedly high momentum ($\sim0.6$ g$\cdot$km/s). The C$_{60}$ NPPJ was obtained by using a solid state TiH$_{2}$/C$_{60}$ pulsed power cartridge producing $\sim$180 mg of C$_{60}$ molecular gas by sublimation and by electromagnetic acceleration of the C$_{60}$ plasma in a coaxial gun ($\sim$35 cm length, 96 kJ energy) with the output of a high-density ($>$10$^{23}$ m$^{-3}$) hyper-velocity ($>$4 km/s) plasma jet. The $\sim75$ mg C$_{60}$/C plasma jet has the potential to rapidly and deeply deliver enough mass to significantly increase electron density (to $n_{e}\sim2.4\times10^{21}$ m$^{-3}$, i.e. $\sim 60$ times larger than typical DIII-D pre-disruption value, $n_{e0}\approx 4\times10^{19}$ m$^{-3}$), and to modify the 'critical electric field' and the runaway electrons (REs) collisional drag during different phases of REs dynamics. The C$_{60}$ NPPJ, as a novel injection technique, allows RE beam-plasma interaction diagnostic by quantitative spectroscopy of C ions visible/UV line intensity. The system is scalable to $\sim1 - 2$ g C$_{60}$/C plasma jet output and technology is adaptable to ITER acceptable materials (BN and Be) for disruption mitigation.