In accordance with an optional feature of the invention, the hollow support structure comprises only a single air outlet.
This may allow a particularly advantageous implementation in many embodiments. It may in many embodiments reduce complexity and/or provide improved air flow for cooling.
In accordance with an optional feature of the invention, the hollow support structure may be substantially cylindrical with the coil being disposed on a flat surface of the hollow support structure.
The hollow support structure 1001 may in many embodiments have a diameter no less than 5 cm and no more than 30 cm, and/or a height no less than 1 cm and no more than 5 cm.
In accordance with an optional feature of the invention, the air outlet is formed inside an innermost winding of the coil.
This may allow a particularly advantageous implementation in many embodiments. It may in many embodiments reduce complexity and/or provide improved air flow for cooling.