Final answer:
The comet-tail artifact is closely associated with high impedance mismatches in ultrasound images, similar to ion tails of comets caused by the solar wind. The ion tail forms when the solar wind's charged particles exert momentum on the ionized gas of a comet, pushing it directly away from the Sun.
Step-by-step explanation:
The comet-tail artifact typically occurs due to a high impedance mismatch in ultrasound imaging. This phenomenon is related to the interaction of sound waves with materials that have highly different acoustic impedances. In the context of cosmic phenomena, the solar wind typically produces a comet-tail artifact in the form of an ion tail on comets. When a comet approaches the Sun, it warms up, leading to the sublimation of ices and the release of dust and gases. This matter forms two tails: a dust tail affected by radiation pressure and an ion or gas tail pushed by the solar wind. The momentum carried by the solar wind's charged particles creates a high-velocity stream that pushes the ionized gas directly away from the Sun, producing the ion tail with a characteristic straight trajectory, which is essentially an impressive display of a comet-tail artifact.