Power dissipation on "litz" type conductors

In the framework of the RF R&D task for the radiofrequency studies to support the SPIDER operation, the analyses of the "litz" wire in harmonic regime has been revised starting from the literature available. This type of conductor is particularly suited for the realisation of low losses inductor at high frequency that is of greater interest also for the design of a high quality resonant circuit. This aspect is exploited and analysed in the RF R&D especially for the realisation of the HVRFTF (High Voltage Radio Frequency Test Facility). The work presented in this note aims in particular to provide a reformulation, in the simple case of a not twisted Litz strand, of the analytical calculation of the equivalent resistance of this type of wire. The work presents the solution in terms of Modified Bessel Function of first kind, a straightforward approach in comparison with the methods usually found in literature. The results of this approach are in agreement with the known analytical results found by Kaden [4].