Particle Transport Due to Magnetic Fluctuations

Electron current fluctuations are measured with an electrostatic energy analyzer at the edge of the MST reversed-field pinch plasma. The radial flux of fast electrons (E>Tₑₐ) due to parallel streaming along a fluctuating magnetic field is determined locally by measuring the correlated product 〈 ̃ \~Jₑ ̃ \~Bᵣ〉. Particle transport is small just inside the last closed flux surface (Γe,mag<0.1Γe,total), but can account for all observed particle losses inside r/a=0.85. Electron diffusion is found to increase with parallel velocity, as expected for diffusion in a region of field stochasticity.