Particle-in-cell Monte Carlo simulations of rf glow discharges between parallel-plate electrodes reveal the possibility of negative period-averaged power deposited into electrons in the body of the glow. A two-fluid model of fast- and slow-electron transport demonstrates that fast electrons are compressed at the plasma-sheath boundary by the expanding sheath and are rarefied at the other (collapsing) sheath, resulting in a fast-electron density gradient through the plasma. The resulting electron acoustic waves are the key to understanding electron cooling in the body of the glow.

• Received 14 December 1990

DOI:https://doi.org/10.1103/PhysRevLett.66.1469