Author/Authors :
Valisa، نويسنده , , M. and Bartiromo، نويسنده , , R. and Bettella، نويسنده , , D. and Carraro، نويسنده , , L. and Costa، نويسنده , , S. and Martin، نويسنده , , P. San Martini، نويسنده , , S. and Pasqualotto، نويسنده , , R. and Puiatti، نويسنده , , M.E. and Scarin، نويسنده , , P. and Sattin، نويسنده , , F. and Telesca، نويسنده , , G. and Zanca، نويسنده , , P. and Zaniol، نويسنده , , B.، نويسنده ,
Abstract :
The standard intrinsic nature of transport in reversed field pinches entails that remarkable ohmic power input (20–80 MW) is involved in the all-graphite, MA level RFX device. MHD instabilities restrict the region of plasma-wall interaction (PWI), where power densities >100 MW m−2 may be locally reached. Means for handling such power have been successfully devised to avoid carbon bloom and allow reproducible experiments around 1 MA of plasma current. Improved confinement schemes (quasi-single helicity, pulsed poloidal current drive (PPCD)) corresponding to a more ordered magnetic configuration have opened new operational perspective in which PWI is a less severe problem. However, in general, plasma contamination is not a specific issue. Screening processes have been associated with low ionisation length to Larmor radius ratios and with the presence of an edge radial electric field. Impurities appear to have a role in the formation of the radial electric field by enhancing the ion prompt losses.
