1. 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

2. Control the Current Profile Control Plasma Rotation
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

3. 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

4. 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

5. Hot spot in NSTX with open field line connection
Depends on antenna spectrum

6. Alcator C-Mod ICRF RF driven erosion on surfaces connected to open field lines
Ameliorated with Boronization – Not workable in DEMO?

7. 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

8. ITER Solutions geared toward ITER Requirements
Need facility that’s allows for antenna development in the presence of challenging plasmas