Impurity release from high Z test limiters immersed in TEXTOR-94 edge plasmas

A W test limiter has been inserted into the plasma edge of TEXTOR beyond the magnetic surface of the main ALT graphite limiter, and the release of neutral W as well as carbon and oxygen are examined spectroscopically. The penetration depth of neutral W has decreased significantly with increasing plasma density and it is as small as 1.2 mm when the local plasma density at the magnetic surface of the limiter increases up to 1.5 x 10(19) m(-3). The flux of neutral W decreases as the local density increases, while the C and D fluxes increase. Radial intensity distributions of CII line spectrum emission have indicated larger penetrations of C ions emitted from a W limiter than those from a C limiter. The penetration length of OII emission from a W limiter is similar to that from a C limiter and much smaller than that of CII.