Investigation of the discharge dynamic resistance in the conditions of stepwise ionization

Abstract

Expressions for the arc dynamic resistance at intermediate pressures have been derived, when charged particles emerge as the result of stepwise ionization and decay on the walls due to ambipolar diffusion. The calculations were performed for two cases: when the metastable levels decay by the electron impact and when the decay occurs on the tube walls as the result of diffusion to the latter. In both cases the impedance has the inductive nature. In case of the decay of metastable levels by the electron impact, the impedance curve begins from the origin of coordinates at ω = 0. As the frequency increases impedance modulus |Z| also increases, reaches its maximum and then drops to the real value equal to the specific resistance of the column. As metastable levels (metastables) decay on the walls as the result of diffusion, the impedance curve begins from the negative real value at ω = 0. The column displays its negatron property and the current-voltage characteristic (CVC) acquires the falling pattern. The theoretical impedance curves obtained by calculation were compared with the measured ones under the properly selected conditions and they were found to be in the qualitative agreement.