A Hall probe uses the Hall effect to measure steady (as well as unsteady) magnetic fields. Often used to verify the designed channel magnetic field strength of constructed thrusters.
Schematic of the actively cooled Hall probe developed by M. Domonkos, et al, in ref. 1, for operation in vacuum with thruster discharge (D55 TAL).
Hall probes use the Hall effect to measure steady magnetic fields.
The principle of how it works is as follows.
A semiconductor resides within a magnetic field.
A current is passed through the semiconductor and the current carriers feel a Lorentz force due to the motion.
This results in a charge build up on the faces of the semiconductor, which creates an electric field.
This additional field cancels the magnetic force and is sensible by electrodes on the semiconductor faces.
The combination of the Hall probe with electronics is often called a gaussmeter.
Shielded, water-cooled hall probes were developed at PEPL, to measure the magnetic field in Hall thrusters during operation.
Both axial and transverse probes were constructed and found to be accurate to within 7 gauss.
Also available at PEPL are several commercial gaussmeters including a 3-axis LakeShore 460 model for measurement from 0.1 gauss to 30,000 gauss.
Selected Relevant Publications
- Domonkos, M. T., Gallimore, A. D., and BilÚn, S., "A Hall Probe Diagnostic for Low Density Plasma Accelerators," Review of Scientific Instruments, Vol. 69, No. 6, June 1998, pp. 2546-2549.