Technology for Polarization Measurement

Tokamak Plasma Diagnostics

A “tokamak” is a plasma fusion reactor in which the plasma is contained by a strong magnetic field.  In 1950, Andrei Sakharov and Igor Tamm conceived the tokamak and the idea of containing it with a magnetic field as a way to allow the plasma to reach high enough temperatures for nuclear fusion.  In 1997, Dr. Fred Levinton, working at the Princeton Plasma Physics Lab, developed the concept of using a Dual PEM-based polarimeter to characterize these tokamak plasmas using the Motional Stark Effect (MSE). For this work, he received the American Physical Society’s Award for Excellence in 1997.

During these MSE experiments, a beam of neutral deuterium atoms is injected into the plasma.  The atoms become excited and emit 656 nm light polarized perpendicular to the surrounding magnetic field.  By analyzing the polarization of the emitted light, scientists are able to determine the direction of the magnetic field in the plasma.  Today, tokamaks throughout the world employ Hinds Dual-PEM polarimeters to characterize their fusion plasmas.

For more detail about the use of the Motional Stark Effect for characterization of magnetic fields in a tokamak plasma, please see the Hinds Newsletter from 2002 on Tokamak Plasma Diagnostics:

Newsletter: Tokamak Plasma Diagnostics


Dual PEMs
Stokes Polarimeters

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