Several alternative concepts require coils that are internal to the plasma which are not easily accessible, or are not accessible at all. Internal coils in a fusing plasma pose challenging engineering issues. The work presented in this poster will address some of these issues in the context of the levitated dipole fusion concept [1,2].

For advanced fuels (D-3He) substantial heating of the coil will occur due to direct charged particle bombardment and due to ionizing radiation (neutron and x-ray). It may be possible to avoid heating due to synchrotron radiation, and indeed, it may be possible to use synchrotron to generate power "onboard" the coil.

Three issues will be discussed: thermal, electrical and mechanical.

Electrical power generation is required internal to the coil for cooling the superconductor. Among the options to be discussed are mechanical storage, thermoelectric generators, multiple thermal cycles, synchrotron conversion and direct conversion. The paper will identify some of the issues with these power generating schemes.

There are several options for the superconductor. Inductive charging is an attractive alternative to charging methods used in Levitrons, including the FM-1. Issues relating to the choice of superconductor, persistency of the superconductor, stability, cooling requirements and quench protection will be addressed.

Finally, mechanical issues having to do with the electromechanical stability of the configuration will be discussed.

[1] E. Teller, A. Glass, T.K. Fowler et al., Fusion Tech. vol 22, 82 (1992)
[2] J. Kesner, M. Mauel, invited paper at the 1997 Sherwood Meeting, Madison, Wisconsin (May 1997).