A vacuum plasma processor includes a chamber having a grounded wall and an outlet port. When charging hydrogen, the blower blows air towards a radiator of the vehicle parked at a predetermined vehicle parking area of the hydrogen station. The interface presents a high and variable source impedance coupling to the scalp. The belt portions can freely pivot with respect to the central support to accommodate the user’s body shape and the user’s movement. Second ends of the third and fourth conductors may be grounded.