The objective of this work is the experimental study of the effect of inhomogeneous magnetic-field-aligned (parallel) ion drift on the destabilization and propagation of electrostatic ion waves. Such inhomogeneous ion velocity is created in the cylindrical barium plasma column produced in a Q-machine. Noninvasive measurements of the ion velocity distribution are performed using the laser-induced fluorescence technique. Multi-harmonic ion cyclotron waves are identified, and experimental evidence is presented that ion cyclotron damping can become inverted to result in net wave growth. For...