Waves in Bopp-Land\'e-Thomas-Podolsky generalized electrodynamics

We investigate the feasibility of probing Bopp-Land\'e-Thomas-Podolsky generalized electrodynamics with traveling and standing wave experiments. We consider wave propagation in vacuum and in a cold and non-magnetized plasma. Dispersion relations are found for all possible transverse and longitudinal modes. Longitudinal traveling waves are found which exhibit negative group velocities.