TJ-II:Magnetic surface mapping
After construction of TJ-II was completed, the accuracy of the magnetic field was checked by measuring the vacuum flux surface mapping and comparing to theoretical predictions. The mapping was done at a magnetic field strength of 10% of the nominal value. The detection process involved imaging the spots produced by electrons, produced by an electron gun, when these intersect an array of fluorescent rods that sweeps the vacuum vessel cross section. [1] The agreement was found to be good. [2]
Flux surfaces. Left column: measured. Right column: calculated. Top row: n=4, n=3. Middle row: n=8, m=5. Bottom row: n=3, m=2. [2]