The TERPSICHORE code is a global linear ideal MHD stability solver that employs hybrid finite elements for the radial discretisation and Fourier decomposition in the angular variables. A transformation from the angular coordinates in ANIMEC to Boozer magnetic coordinates is performed because this frame is more appropriate to follow guiding centre particle orbits and evaluate MHD stability. The normal and binormal components of the displacement vector are the outputs from which the electrostatic potential and the vector potential can be calculated.terpsichore helitron