The ionosphere doesn't have a single, commonly used alternate name. However, it's sometimes referred to as the thermosphere because it's located within this layer of the atmosphere.

It's important to note that the thermosphere and the ionosphere are not identical. The thermosphere is defined by its temperature profile, while the ionosphere is defined by the presence of ionized particles. The ionosphere overlaps with the thermosphere, but it also extends slightly into the mesosphere above and the exosphere below.

Here are some other less common terms you might encounter:

* Kenelly-Heaviside layer: This refers to a specific layer within the ionosphere discovered by Arthur Kennelly and Oliver Heaviside.

* Upper atmosphere: This is a general term that encompasses both the thermosphere and the ionosphere, along with the mesosphere and exosphere.

Ultimately, the best term to use depends on the context of your discussion. If you're focusing on the ionization properties, "ionosphere" is the most accurate. If you're discussing temperature, "thermosphere" might be more appropriate.