Reversed Tokamak

The reversed field pinch (RFP) is a closely related configuration, since the plasma formation and ohmic heating are essentially identical to the tokamak. However, in the tokamak the average poloidal field is limited by stability requirements to approximately an order of magnitude smaller than the toroidal field, whereas the two are of similar magnitude in the RFP, both being typically less than 1 Tesla. 

The associations are the backbone of the fusion programme. They operate a number of fusion devices in their laboratories (see Table 7.7). Most of these fusion devices have been built along the tokamak principle, but there are also stellarators and reversed field pinches. And there are a number of facilities for technological development such as large superconducting-magnet-testing facilities. 

The plasma physics basis for CT reactor projections is derived from MHD stability theory and experimental observations of macrostability, and from postulated transport scaling or scaling of related devices (tokamak and diffuse, toroidal pinch). A central issue, on which different reactor projections can be based, centers on the observed macrostability of certain CT s (reversed field theta-pinch Toroidal apparent contradiction with MHD stability theory. Although the conflict may be resolved by inclusion of finite-ion-larmor radius (FLR) effects in the theory, scaling assumptions to reactor conditions may or may not invoke FLR. 

In the same way we could fuel the field-reversed configuration. The transport scaling in the field-reversed configuration, is very different from that in other toroidal systems such as the reversed-field pinch , spheromak and tokamak. I say this because there is no shear in that system at all. Some instabilities are... 

A fairly complete first order reactor design has been done for the field-reversed configuration both for the TRACT and the moving-ring system CTOR, but it is very low level in comparison with the tokamak reactor designs. I am not so familiar with the spheromak reactor designs. I don t know whether anyone else can comment on them. This is all I have to say about those two configurations. It is perhaps time to open up for comments. 

As the charged particles flow round the torus, they create a magnetic field around it. In ZETA, the magnetic field created by the coils around the torus was less than the field produced by the current. In a tokamak, the reverse is true, making for a much more stable plasma. 

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