Abstract
The first two harmonics generated in a microwave discharge in which a weak dc field is present are calculated. The mechanism by which harmonics are generated is assumed to be a modulation of the electron collision frequency by the microwave field. The second harmonic is strongest at a pressure for which the collision frequency is well below the frequency of the perturbing microwave field. The third harmonic is strongest when the collision frequency is approximately equal to the frequency of the microwave field. These results are found to be in reasonable agreement with the observations of Uenohara.