Scientists at Princeton Plasma Physics Laboratory (PPPL) have developed a new method that eliminates the solenoid that is used to inject current into their reactor. Compact Spherical Tokamaks, which are apple shaped, have traditionally used this core solenoid to deliver the current. The new design called Transient Coaxial Helical Injection (CHI) instead uses electrodes at the top and bottom of the core that produces the same result. The other good news is that CHI appears to scale up for larger reactors. Although it is currently being modeled using software there are planned experiments using the URANIA tokamak at UW-Madison.
Read more here: