  In recent years, interest in striation phenomena in radio-frequency (rf)
discharges has risen due to the availability of new experimental data and
implementation of new computational models. Depending on the conditions,
different mechanisms of discharge striations are realized. These are the
ionization instability, the instability due to the electron attachment to
electronegative gases or the instability due to thermoelectric transport.
Although the first two mechanisms were modeled quite extensively in recent
years, the understanding of the influence of Dufour effect originating from
plasma density gradients on stability of radio-frequency discharges in long
tubes remains poor. In this paper, the influence of this mechanism on the
longitudinal striations of radiofrequency discharge is presented using a
one-dimensional model of argon discharge driven with rf excitation under
intermediate pressure conditions of 0.5 Torr. It is found that striation
formation is sensitive to the value of the thermoelectric heat transport
coefficient in the low electron temperature range. The critical value of this
coefficient necessary for the instability onset is derived using the linear
stability analysis.
