inDEMOEnvironmentandRequirementstoAddressthe.ppt

The Problems of RF Launchers in DEMO Environment and Requirements to Address them J.R. Wilson, R.J. Goldston, J.C. Hosea ReNew Theme III Workshop UCLA March 5, 2009 RF Wave Energy is used for a variety of purposes on present devices and is proposed to be used on an AT DEMO to: Heat the plasma Control the Current Profile Majority Bootstrap CD Control Plasma Rotation Control MHD Stability NTM stabilization Other concepts will have similar requirements Challenge While there are some issues with wave propagation and absorption in the core plasma, a large class of challenges involve the launchers and their interaction with the scrape-off plasma Issues possibly addressed on ITER Power Density How much real estate is allowable? Delicate components close to plasma ECH mirrors LH waveguide vanes ICH Faraday screen Power deposition in scrape off plasma LH fast electrons ICH SOL sheaths Unacceptable modification of pedestal Hot spot in NSTX with open field line connection Depends on antenna spectrum Alcator C-Mod ICRF RF driven erosion on surfaces connected to open field lines Ameliorated with Boronization – Not workable in DEMO? Issues not addressed on ITER Launchers will operate at high temperature New cooling techniques required Launchers will operate in a significant radiation environment Will require new materials ITER Solutions geared toward ITER Requirements Need facility that’s allows for antenna development in the presence of challenging plasmas