Equilibrium characteristics of strong ion sheaths in a partiallyionized plasma

Experiments have been carried out to study the equilibrium characteristics of strong ion sheaths (eΦ/T_e≫1) in a partially ionized argon plasma. An improved method of potential measurement in the sheath is described. The potential profile shows deviations from Child's law and the reduction of sheath size with pressure. Energy analysis of ions reaching the negative biased electrode show that the ions are not monoenergetic but have a spread in energies which depends on neutral pressure