Energy flux investigation in the outer region of the ETA BETA II experiment

The energy transport in the outer region of the RFP experiment ETA BETA II has been experimentally investigated by measuring the energy flux intercepted by the surface of an insertable limiter, instrumented with heat flux probes. It has been found that the energy deposited on the surface facing the electron flow is almost an order of magnitude larger than that deposited on the opposite side. The spatial dependence of the energy flux has been studied and the results are reported for different main plasma densities. The results are explained by fast electrons flowing in the outer region of the plasma, parallel to the magnetic field in agreement with the results found in other RFP experiments.