Collisionless heating in low-pressure capacitively coupled rf discharges is usually attributed to a stochastic interaction between electrons and the oscillating sheath. We show that this explanation is not complete—there is a powerful heating mechanism associated with pressure effects that arise during the expansion and contraction of sheaths.

• Received 28 March 1995

DOI:https://doi.org/10.1103/PhysRevLett.75.1312