Transient waves in a piezoelectric half-space generated by line-loaded surface sources

Precise algebraic expressions of the wave fields generated by line-loaded impulsive sources exerted on the piezoelectric surface are given. The analysis reveals three types of main singularities (modes): the five characteristic modes (two quasi-electromagnetic, three quasi-acoustic) allow in one propagation direction at most 45 wavefront arrivals of (t-t₀)^-(1-1/λ) singularity and R^-1λ/ decay in the interior, where t₀ is the arrival time, R is the distance from the source line, and λ⩾2 is an integer depending on the geometry of the cylindrical wavefront (on the surface, characteristic modes have the same singularity and decay characteristics as head waves); numerous head waves occur between coupled characteristic modes, having planar wavefronts, (t-t₀)¹λ/ singularity and R^-(1+1/λ) decay (λ⩾2), as well as an extremely simple directivity pattern; and one or two surface wave(s) of nondecaying δ(t-t₀) plus δ( t-t₀^-1 singularities may exist on the surface, under which fields decay inversely with the depth. Numerical results are presented graphically to illustrate and justify the analytical results