Power source systems implementing methods for reducing vertical segregation (color mixing) in a long and thin high intensity discharge lamp are disclosed. Each system provides a current frequency signal to the lamp that excites an azimuthal acoustic and longitudinal acoustic combination mode of the lamp...http://www.google.ca/patents/US6437517?utm_source=gb-gplus-sharePatent US6437517 - Method and system for exciting an azimuthal acoustic and longitudinal acoustic combination mode
