Use of Mach probes and Langmuir probes in a drifting unmagnetized nonuniform plasma

Summary form only given. Although Mach probes have been used to measure the ion drift velocities in fusion plasma applications, their operation in unmagnetized plasma is less well understood. The effects of nonuniform drifting plasma on Langmuir probes and Mach probes have been investigated in a multi-dipole plasma. A circular conducting plate was mounted into the multi-dipole chamber. A Mach probe consists of two single sided Langmuir probes back to back, Mach probe theory was used to determine the ion drift velocity from J/sub U//J/sub D/=exp(ku/sub m/) where J/sub U/,J/sub D/ are the upstream and downstream currents, k is constant, u/sub m/ is the Mach number. The Mach probe data were collected for different probe sizes and for different noncollecting part biases.