The Fraunhofer zone is also known as what?

The Fraunhofer zone is indeed known as the far zone in ultrasonic terminology. This region refers to the area where the sound waves have spread out sufficiently that the wavefronts can be approximated as planar waves. In the context of ultrasound, this occurs beyond the near zone or Fresnel zone, where the waves are still converging and exhibit more complex geometries.

Understanding the Fraunhofer zone is important because it is where the characteristics of the ultrasound beam stabilize, leading to a more uniform intensity distribution and improved resolution for imaging. This is crucial in clinical ultrasound, as it allows for better visualization of structures and accurate measurements.

In contrast, other zones such as the near zone (Fresnel zone) involve more complex wave behavior where the sound propagating through the medium is more divergent, resulting in less clarity and higher variability in image quality. The focus zone specifically refers to a point along the beam path where the focus is achieved and does not encompass the broader characteristics of the far zone. The phase zone is not a commonly used term within the context of ultrasound zones, making it irrelevant for this comparison.