In both serious and less serious electrical engineering literature, there is a great deal of misunderstanding about what "Scalar Waves" are. This volume explains that these waves are hypothetical longitudinal waves.
 
It is demonstrated that a longitudinal wave is made up of both a scalar potential and a vector potential. Acoustic waves have a complete analog in other media. There is also a discussion of longitudinal electromagnetic wave transmitters and receivers.
 
The scalar wave is a component of the More Complete Electromagnetic (MCE) equation, which is an extension of Maxwell's equation. However, a Scalar Wave refers to a type of wave that is characterized by scalar quantities, which are quantities that only have magnitude and no direction.