Initial Result of Neutron Emission Rate Analysis for Ion Cyclotron Range of Frequency Heated Deuterium Plasmas in LHD

Abstract

A database of the total neutron emission rate (S_n) in the ion cyclotron range of frequency (ICRF) heated deuterium plasma in the Large Helical Device (LHD) was developed with changing the ICRF injection power and electron density. The S_n measured in the experiment was compared with the neutron emission rate calculated by the thermal reactivity of deuterium plasma to predict S_n in long-pulse discharge and to understand the heating scheme of ICRF. The ratio of S_n evaluated by calculation and that by measurement in the electron cyclotron heating (ECH) and ICRF heating case has almost the same tendency as that of the ECH only case in which energetic deuterons are not expected. In the first campaign of deuterium ICRF plasma discharge with injection power up to 1.5 MW, neutron emission with regard to the ICRF tail deuteron was thought to be negligible. We expanded the S_n database and started building an S_n prediction code to perform a long-pulse deuterium discharge.