What is ionospheric bending?

When a radio wave travels into the
ionospheric layer it experiences refraction due
to difference in density. The density of
ionospheric layer is rarer than the layer below
which causes the radio wave to be bent away
from the normal. Also the radio wave
experiences a force from the ions in the
ionospheric layer. If incident at the correct
angle the radio wave is completely reflected
back to the inner atmosphere due to total
internal reflection. This phenomenon is called
ionospheric reflection and is used in mobile
communication for radio wave propagation
also known as ionospheric bending of radio
waves.