Reversed-field pinches worldwide.
Apart from EXTRAP T2R here at KTH, there are currently two more active RFP experiments:
It was recently (2011) announced that a brand-new Chinese RFP is to be built the coming years.
RFX-mod (R=2.00m, a=0.46m) is larger than EXTRAP T2R (R=1.24m, a=0.18m) and carries a plasma current which is an order of magnitude higher than does T2R. RFX-mod is equipped with feedback coils in a way similar to T2R as depicted below.