The Æther Field is a hypothesized field that permeates all of reality. The concept takes great inspiration from Quantum Field Theory. Like fundamental quantum fields, the Æther Field exists at every point in space-time and can be displaced, excited, or distorted.
Excitations within the Æther Field correspond to consciousness or affects of consciousness. All conscious entity generate disturbances in the field (see the pond analogy), but only magi can intentionally manipulate it through spell or Sentia sequencing. Through such manipulation, the Æther Field can be made to interact with or mimic other physical fields, such as the photon (quantum), gravitational or electromagnetic fields. This, in essence, is how spells affect reality.
A simple example of quantum field interactions is how electrons affect one another through the photon field. In a similar fashion the Æther Field can affect the electron to. In this sense, the Æther Field is meant to be the master field of QFT from which all other fields arise.
The high-level sequence for interaction is the following: Magi/conscious entity ⇒ Æther Field disturbance ⇒ Influences fields (based on intent) through QFT ⇒ Quantum field interact brings about physical change .