Flux loop

A flux loop is a loop of wire placed inside a plasma at a right angle. Changes in the field create a current in the loop, which may be interpreted to measure the properties of the plasma. Flux loops are key diagnostics in fusion power research.

Theory

A very basic flux loop

A flux loop is a loop of wire. The magnetic field passes through the wire loop. As the field varied inside the loop, it generated a voltage, driving a current. This was measured and from the signal the magnetic flux was measured. The voltage induced is determined by:

$voltage(Time)=NumberofLoops*Area*{\frac {dMagneticField(time)}{dtime}}$

Typically, you need to integrate the signal over a period of time to get the magnetic field at that instant (not just the change in magnetic fields). This is normally done by adding a integrator circuit which will passively integrate the electrical signal.

$voltage={\frac {NumberofLoops*Area*MagneticField}{resistance*capacitance}}$

Flux Loop with Circuit Integrator