Effect of Microwave Power on Electron Temperature and Electron Density in Deuterium Plasma Generated by Electron Cyclotron Resonance

Abstract

The desire for continuously gaining new knowledge in fusion reactor technology has pushed the frontier of engineering methods to deliver highly stable ion source for 14-MeV neutron generators. The diagnostic of the ion source of 14-MeV neutron generator is one of the prime concerns for future fusion reactor technology. An accelerator-based 14-MeV neutron generator is developed at Fusion Neutronics Laboratory of Institute for Plasma Research, Gandhinagar, India. The ion source of this 14-MeV neutron generator is diagnosed via the optical emission spectroscopy technique. In order to achieve optimum electron temperature and electron density for stable operation of ion source, the controlling parameters, namely, deuterium ambient gas pressure, ambient gas flow rate, and microwave power coupled to the deuterium plasma, are varied systematically. An investigation on the effect of microwave power coupled with deuterium plasma on the overall electron temperature as well as electron density is investigated in this paper. Prominent Balmer emission lines of deuterium $\alpha $ , $\beta $ , and $\gamma $ ( $\text{D}_{\alpha }$ , $\text{D}_{\beta }$ , and $\text{D}_{\gamma })$ are observed in the deuterium plasma generated by electron cyclotron resonance. The overall electron temperature of deuterium plasma is measured by Boltzmann plot at various microwave power, 100–400 W, whereas the electron density is measured by Stark broadening.