[en] Additional heating of strongly elongated high-β plasmas by fastmagnetosonic-wave absorption at the second harmonic of the ion cyclotron frequency (ω=2ωsub(ci)) was investigated in the Belt-Pinch HECTOR. Fast Alfven-waves with toroidal and poloidal mode numbers n=0 and m=0, respectively, were launched radially into the plasma by modulating the confining magnetic field with a frequency of 1.2 MHz during 5 μs. The experiments were performed under various plasma and resonance conditions in regimes where the ion gyroradii are comparable to the perpendicular wavelength. When the resonance layer is located in the plasma centre efficient wave absorption with an energy flux of about 50 MW/m² was observed. The β-value on the magnetic axis increased from 30% to 70% indicating a localized power deposition. The ion temperature grew nearly linearly with increasing incident wave power up to Tsub(i)(r=0)=250 eV at a modulation degree of delta B/B approx.= 0.2 (Psub(in) approx.= 200 MW). The electron temperature is unaffected by the wave and remains almost constant. In corresponding hydrogen discharges, where the resonance region ω=2ωsub(ci) is located outside the plasma no heating was observed. During the RF-heating process and the following energy decay the plasma passes through a sequence of flux-conserving equilibria. This was demonstrated by numerical calculations starting from experimental input parameters using a free-boundary 2d-equilibrium code. (orig./AH)