Neutron emission rate characteristics of an electron cyclotron heated Large Helical Device deuterium plasma

The total neutron emission rate (S_n) characteristics of electron cyclotron heated plasma were surveyed in the Large Helical Device in order to exhibit the thermonuclear performance of helical plasma. The dependence of S_n on electron density showed that S_n increased with an electron density of power of 3.1. To understand S_n, characteristics in the electron cyclotron heated plasma, a numerical simulation considering thermal deuterium-deuterium fusion reactions was performed. Although the numerical simulation overestimated S_n in a relatively low S_n region, calculated S_n matched the experimental result for a relatively high S_n region. A possible reason for the disagreement in the low S_n region is that effective charge due to the impurities such as carbon is changed because of the low density. (author)