The enhanced tomographic electron density interferometer for the H-1NF heliac

A tomographic three-view 39-beam far-infrared (λ =433 μm) interferometer has been installed and operated on the H-1NF heliac. The system has unprecedented tomographic capability allowing the distinction of global modes of different helicity and rotation frequency. A number of enhancements are in progress to upgrade the existing system to enable it to be used as a powerful routine diagnostic on H-1NF. These include: use of longer wavelength (λ =743 μm) far-infrared radiation for greater sensitivity for low plasma density studies; improved reconstruction of the plasma profile by increasing the number of views of the plasma and the coverage of the plasma within each view; independent mounting of the rotating grating wheel to eliminate vibrational noise and integration of the tomographic reconstruction algorithm with the H-1NF data viewing software