Feasibility of local power losses determination in the TJ-II heliac using movable bolometers

A method to fully diagnose energy losses in plasma devices with a reduced experimental setup is presented. This technique is based on the use of single movable detectors instead of full detector arrays, and it is especially suitable for devices with large toroidal and/or poloidal asymmetries, such as the TJ-II flexible heliac, that would require a large number of measurements at different positions. Local distributions of the plasma losses are deduced from the bolometer signals by using general tomography algorithms. The number of lines of sight is only limited by the sensitivity of the detector and the number of reproducible shots in the device, and, as a consequence, the possibility of obtaining a well-defined mapping of the plasma energy losses can be even better than in the standard case based on the use of detector arrays with a fixed number of detectors. The method has been tested in the TJ-I tokamak and the results obtained are presented, together with a simulation of its application to the TJ-II heliac