Charging and heating processes of dust particles in an electron cyclotron resonance plasma

Incandescent dust particles are observed with the naked eye in plasmas excited at the electron cyclotron resonance produced in pure acetylene. To investigate the heating mechanisms involved and their potential impact on the dust particle charge, as a first approach, a probe is used to measure the floating potential and to estimate the temperature reached by the material. Both highly depend on the position in the magnetic field and on the plasma conditions (pressure and gas, namely argon or helium). Numerical simulations based on the balance of the currents and of the heat fluxes on the probe emphasize a key role of primary electrons: they are responsible for the very negative floating potential as well as for the high probe temperature. Numerical simulations are also adapted to the case of a dust particle in a non-reactive plasma. However, even it can reach temperatures higher than 1600 K, the dust particle remains negatively charged.