One characteristic fundamental to phased array is that the wavefront is composed of?

Phased array technology relies on the principle of superimposing multiple wavelets to create a desired wavefront. The correct answer highlights that the wavefront is composed of wavelets or secondary waves. When operating a phased array system, each element in the array can be excited at different times, causing them to emit waves that combine constructively or destructively. This constructive interference leads to the formation of a specific wavefront, which can be directed in different angles or focused, allowing for flexible and precise control over the ultrasonic waves being used for inspection.

Understanding that the wavefront is generated from wavelets highlights a crucial aspect of phased array technology, specifically how it manipulates the phase and timing of signals from each element to form a coherent beam. In contrast, the other options refer to different types of waves or phenomena not specific to the operating principles of phased array systems. This distinction is key in mastering the concepts surrounding phased array inspections, as it informs how the technology is utilized in practical applications.