Density and temperature measurements of pulsed plasma produced inside a curved vacuum chamber

Recent experimental evidence suggests the importance of fast radial plasma transport in the scrape-off-layer (SOL) of tokamaks. The outward transport appears to be convective rather than diffusive, extends into the far SOL, and can produce significant recycling from the main-chamber walls, partially by passing the divertor. A plausible theoretical mechanism to explain this phenomenon is the radial transport of locally dense plasma created by turbulent processes. In our experiment a blob of plasma is produced using a plasma-gun and injected radially to the curved vacuum chamber. In this paper we report the measurement of electron density and temperature of the plasma blob produced by the plasma-gun inside the curved vacuum chamber using cylindrical Langmuir probes. The probes are moved both radially and transversely to flow direction. The electron density and temperature are measured ∼ 1016 m-3 and 10-1 eV respectively for radial flow at constant discharging potential, base pressure as well as plasma pulse time.