Observation of Alfv\'{e}n eigenmodes in reversed-field pinch plasmas

High frequency (up to 1.5 MHz) Alfv\'{e}n eigenmodes have been detected in the RFX-mod reversed-field pinch (RFP) device by means of insertable edge magnetic probes. The Alfv\'{e}nic nature is deduced by the linear relation between the Alfv\'{e}n velocity of the investigated plasmas and the measured frequencies. A wide range of experimental conditions have been explored in terms of plasma current (0.4-1.8 MA), electron density (0.5-8 x 1019 m-3) and working gas (H and He). The coherent activity has been clearly observed on the parallel component of the magnetic field, which, at the edge of the RFP, is the poloidal one. Two distinct kinds of modes have been observed: the first consists of two modes together and continuously present during the discharges at two frequencies above 500 kHz; the second, at a lower frequency appears during the so-called Single Helical Axis states characterizing the high current discharges of RFX-mod.