Two simple methods of estimating the plasma position in a large-aspect-rati
o, low-beta(p) tokamak with an iron core transformer are demonstrated: a ma
gnetic diagnostic method and an optical method. The magnetic diagnostic met
hod utilizes an array of magnetic pickup coils to measure the poloidal magn
etic field produced by the plasma current. To include the effects of toroid
icity and an iron core transformer, the correction factor was calculated wi
th the magnetic material (or iron core) inside the calculation domain and i
ncorporated in the analysis. The evolution of horizontal and vertical displ
acement of the plasma center obtained in this way is used to control the KA
IST-Tokamak plasmas. To compare the plasma position estimated using the mag
netic pickup coils, a simple optical method is also demonstrated on KAIST-T
OKAMAK using a composite video signal from a charge-coupled device (CCD) ca
mera. The two results are in good agreement.