Extending the total neutron emission rate of steady-state deuterium large helical plasma guided by a data-driven approach

•A trial for extending the total neutron emission rate was performed in steady state deuterium large helical plasma.•A quantitative guidance is acquired by regression analysis for updating neutron emission rate record in gas puff discharge.•The neutron emission rate record was successfully updated in a steady state discharge with the regression expression.•Such a approach is effective for the gradual extension of total neutron emission rate beyond the employed database. A trial for extending the total neutron emission rate (Sn) was performed in the Large Helical Device (LHD) deuterium plasma experiment using a gas puff in order to show the way to realize a steady-state fusion reactor. In the 22nd experimental campaign of the LHD, a high Sn discharge was performed by the experimental scenario guided by a data-driven approach. A regression analysis of Sn was conducted beforehand using the externally controllable parameters based on the database of the previous three campaigns. Then, the high Sn record was successfully updated to be 3.7 × 1015 n/s in a steady-state discharge during the 22nd campaign in line with the regression expression. This study demonstrates that such a data-driven approach is effective for the gradual extension of Sn beyond the employed database.