No, I am not and had difficulties finding hints. Eventually I found https://www.ti.com/lit/ml/slup129/slup129.pdf https://www.ti.com/lit/ml/slup129/slup129.pdf

No, I am not and had difficulties finding hints. Eventually I found https://www.ti.com/lit/ml/slup129/slup129.pdf https://www.ti.com/lit/ml/slup129/slup129.pdf which I found helpful. "Magnetic Amplifiers Although called a magnetic amplifier; this application really uses an inductive element as a controlled switch. A mag amp is a coil of wire wound on a core with a relatively square B-H characteristic. This gives the coil too operating modes: when unsaturated, the core causes the coil to act as a high inductance capable of supporting a large voltage with little or no current flow. When the core saturates, the impedance of the coil drops to near zero, allowing current to flow with negligible voltage drop. Thus a mag amp comes the closest yet to a true "ideal switch" with significant benefits to switching regulators."