There isn't a single, widely used alternate name for the ionosphere. However, here are some terms that relate to the ionosphere or describe its characteristics:

* Thermosphere: The ionosphere is embedded within the thermosphere, a layer of the Earth's atmosphere above the mesosphere.

* Heaviside Layer: This name, proposed by the British physicist Oliver Heaviside, was initially used for the reflecting layer of the ionosphere.

* Kennelly-Heaviside Layer: This term recognizes both Oliver Heaviside and Arthur Kennelly who, independently, predicted the existence of the reflecting layer of the ionosphere.

* Radio-reflecting layer: This term highlights the ionosphere's crucial role in radio wave propagation.

* Charged layer: This term emphasizes the presence of charged particles in the ionosphere.

While the ionosphere itself doesn't have a widely recognized synonym, these terms offer different perspectives on its nature and function.