Linear propagation and absorption of ion Bernstein waves in toroidal geometry

The ion Bernstein wave (IBW) propagation is investigated in toroidal geometry with particular regard for the absorption mechanism of the power along the trajectory which shows a strong dependence on the value of the poloidal angle at the antenna. A large power fraction launched by poloidally wide antennas turns out to be absorbed in the very edge of the plasma by electron Landau damping and no penetration of the wave up to the plasma core is allowed except for rays starting at poloidal angles very close to the horizontal plane. This result could provide an explanation for the absence of efficient core heating in some of the IBW heating experiments.